docs: hierarchy schema contract (S2 contract 1, D2) (#1435)

docs/requirements/hierarchy-schema.md

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+# Hierarchy Schema Contract (D2)
+
+Status: DRAFT — awaiting ratification (webui-audit S2, contract 1 of 9).
+Authority: PRD D2/D9/D13 (Part I §4) and the native-kanban SOT Amendment A1
+(`docs/requirements/native-kanban-sot.md` §8, ratified 2026-08-25). This
+document turns the ratified hierarchy into a concrete schema contract:
+tables, cardinalities, constraints, and ownership/transfer semantics. It is
+the prerequisite for the hierarchy command family and for the RBAC grant
+model (contract 2, `docs/requirements/rbac-grant-model.md`).
+
+Revision 2 (independent review, GPT-5.6 terra): tenancy-FK exemption made
+explicit (§1.1); record class extended to include `hierarchy_grants`
+(§1.1); provenance corrections on legacy tables and the planning `projects`
+table (§1.3, §2 naming note); NOT NULL and `NULLS NOT DISTINCT` grant
+uniqueness (§2.6, §3.2); grant FK delete actions split cascade/restrict
+(§3.3); transfer transaction includes its audit write (§4.3); ownership
+invariant completed via contract 2 with the both-sides rule marked as new
+policy (§4.2, §4.4); hierarchy audit brought under REQ-AUD-001-equivalent
+guarantees with deletion-safe linkage (§5.2); roll-up never-a-write restored
+to full A1 strength (§5.4); §6 rebuilt with bounded observables for every
+MUST (allowlist, command surface, audit, corrected cardinality witness).
+
+Revision 3 (terra re-review residuals): §4.3 transfer write inventory
+reconciled with §5.2 — the transaction's writes are the single class-row
+mutation plus that mutation's §5.2 audit writes (event + outbox record),
+not "exactly two writes"; §6.3 extended with a closed writer-coverage
+witness so an unregistered internal writer cannot pass a registered-route
+inventory. (Terra's finding-8 residual — a stale contract 2 §7.8 backlink
+to contract 1 §6.2 — was already fixed in contract 2 revision 2, which
+cites §6.5; measured against `origin/contract/rbac-grants` head
+`501112d2`.)
+
+Revision 4 (terra r3 residual F7): the §6.3(b) writer-coverage assertion
+extended to raw SQL — it now also fails on class-table name literals
+inside SQL strings or tagged SQL templates outside the allowlist, so a
+raw-SQL writer that touches no schema symbol is still caught.
+
+Revision 5 (terra r4 residual F7): §6.3(b) gains a third prong — any
+raw-SQL execution primitive outside the allowlist fails the assertion
+regardless of its SQL content, closing the evasion where a
+dynamically constructed table name carries neither a schema symbol nor
+a class-table literal. The detection claim is now coextensive with
+what the three prongs statically see.
+
+Revision 6 (terra r5 residual F7 + new F8): the "two prongs" wording
+corrected to three (F8); §6.3(b) gains the allowlist composition rules
+(no generic raw-SQL helper is allowlisted; an allowlisted module may
+not export caller-supplied-SQL execution) and fails outright on
+runtime code-construction primitives; the detection claim is scoped
+honestly to the stated syntactic forms, with evasions beyond static
+reach assigned to §5.1 review/audit rather than claimed for CI.
+
+Revision 7 (terra r6 new F9): the false-positive remedy no longer
+contradicts the composition rules — legitimate non-hierarchy raw
+execution (e.g. the db package's migration runner) is dispositioned
+onto a second closed enumerated list, the infrastructure register,
+exempt from prong (iii) only, still bound by prongs (i)/(ii), barred
+from the writer allowlist, and importable only by registered modules
+or the operational entry points.
+
+Revision 8 (terra r7 residual F9): the register's import rule made
+satisfiable by the live tree — imports are checked re-export-aware
+(package barrels followed), and each registered module carries its own
+closed importer enumeration, which may name operational entry points
+such as the Gateway's startup migration hook; named importers stay
+subject to prongs (i)/(ii) and gain no writer standing.
+
+Revision 9 (terra r8 F10): revision 8 called the Gateway database
+module the runner's "one live importer today". That was false — the
+measured production importer set has four members. The enumeration
+example now lists the complete measured set, and the import analysis
+is extended to resolve literal dynamic `import()` routes, which two of
+the four members use.
+
+Scope: the tenancy/authorization structure record class — companies,
+estates, platform-projects, workspaces, hierarchy grants, their parentage,
+and constraints. Out of scope: the RBAC grant vocabulary and evaluation
+semantics (contract 2), roll-up projection semantics (contract 8), kanban
+planning entities inside workspaces (SOT §5), migration or retirement of
+legacy flat data (future work; see §1.3).
+
+## 1. Record class and placement
+
+1. The **tenancy/authorization structure record class** defined by
+   Amendment A1 §8.1.2 comprises five tables: the four node tables of §2
+   AND `hierarchy_grants` (§3) — A1 includes hierarchy-level access grants
+   in the class. Every rule addressed to "the class" in this contract
+   (payload prohibition, mutation path, audit) binds all five tables. Class
+   rows carry parentage, naming, grant, and audit-linkage data only — never
+   task, plan, or any business/orchestration payload.
+   References from business/orchestration rows into the class are limited
+   to exactly one form: the canonical `workspace_id` tenancy column that
+   REQ-TEN-001 requires on every canonical row, referencing
+   `workspaces.id`. No business/orchestration row may reference a company,
+   estate, platform-project, or grant id in any position, and no
+   business/orchestration row may reference a workspace id in any
+   non-tenancy position (dependency, claim target, work subject).
+2. Hierarchy records are NOT workspace-scoped rows: REQ-TEN-001's
+   `workspace_id` obligation binds business/orchestration rows and does not
+   apply to this class (A1 §8.1.2). The `workspaces` table itself is the
+   anchor the obligation points at.
+3. The legacy flat tables (`teams`, and the Brain planning `projects` table
+   in `packages/db/src/schema.ts`) are not part of this class. What A1
+   §8.1.4 pins is narrower: the planning `projects` table and
+   `platform_projects` stay distinct tables. This contract adds, as new
+   policy ratified here: neither `teams` nor `projects` is repurposed as a
+   hierarchy table. Their eventual migration or retirement is future work
+   that no existing REQ assigns; it is out of scope here.
+
+## 2. Tables and cardinalities
+
+Naming: the level above workspaces is `platform_projects`, per A1 §8.1.4.
+The existing `projects` table is Brain planning data (so labeled in
+`packages/db/src/schema.ts`; it carries no `workspace_id`), and the schema
+MUST NOT merge the two. (A rename of either remains an implementation-PR
+decision under A1; this contract pins only that they stay distinct tables.)
+
+1. `companies` — id (uuid pk), name, slug (unique per deployment),
+   created_at, updated_at. N per deployment (D2).
+2. `estates` — id, name, slug, `company_id` NOT NULL →
+   `companies.id` ON DELETE RESTRICT. Exactly one company per estate; a
+   company holds any number of estates.
+3. `platform_projects` — id, name, slug, `estate_id` NOT NULL →
+   `estates.id` ON DELETE RESTRICT. Exactly one estate per
+   platform-project; an estate holds any number of platform-projects.
+4. `workspaces` — id, name, slug, `platform_project_id` NOT NULL →
+   `platform_projects.id` ON DELETE RESTRICT. Exactly one platform-project
+   per workspace. This table is the referent of every `workspace_id` column
+   the SOT requires on canonical rows.
+5. **Chain resolution is by construction.** Because every parent FK is NOT
+   NULL and single-valued (one FK column, no parentage edge tables, no
+   multi-parent forms, no nullable "detached" states), each workspace
+   resolves to exactly one platform-project → estate → company chain (A1
+   §8.3 acceptance 1). One-parent-per-child is the constrained direction;
+   many children per parent is valid data.
+6. **Slug scoping.** All `name` and `slug` columns are NOT NULL.
+   `estates.slug` is unique within its company, `platform_projects.slug`
+   within its estate, `workspaces.slug` within its platform-project
+   (composite unique constraints). Display names are unconstrained beyond
+   NOT NULL.
+7. No hierarchy table carries a `metadata` jsonb column or any
+   free-form payload field. The columns declared in this section and §3
+   are exhaustive: a class table's column set is exactly its declared set
+   (verified per §6.2) — nothing else (A1 §8.1.2).
+
+## 3. Grant attachment points
+
+The grant vocabulary (which roles exist, what each permits, how evaluation
+and revocation work) is contract 2. This contract pins only the schema
+shape contract 2 attaches to:
+
+1. `hierarchy_grants` — id, subject (exactly one of `user_id` → `users.id`,
+   `team_id` → `teams.id`; CHECK-enforced exactly-one-of), target (exactly
+   one of `company_id`, `estate_id`, `platform_project_id`;
+   CHECK-enforced exactly-one-of), `role` (text NOT NULL; vocabulary and
+   its CHECK constraint owned by contract 2 §2), `granted_by` NOT NULL →
+   `users.id`, created_at.
+2. Uniqueness: at most one grant row per (subject, target, role). Because
+   the subject and target columns are nullable by design, ordinary
+   PostgreSQL composite uniqueness treats NULLs as distinct and would not
+   enforce this. The implementation MUST use a single
+   `UNIQUE NULLS NOT DISTINCT` constraint across (`user_id`, `team_id`,
+   `company_id`, `estate_id`, `platform_project_id`, `role`) or six
+   equivalent partial unique indexes (one per subject×target form). The
+   pinned Drizzle ORM supports `nullsNotDistinct()`.
+3. Delete actions are split by column class:
+   - Target FKs (`company_id`, `estate_id`, `platform_project_id`):
+     ON DELETE CASCADE — the one permitted cascade in this class. A grant
+     on a deleted node is meaningless and fail-open if retained. Cascaded
+     grant deletions are audited per §5.2.
+   - Principal FKs (`user_id`, `team_id`, `granted_by`): ON DELETE
+     RESTRICT. The identity contract (§7.3) gates user deletion today and
+     defines no team-deletion rule; this contract does not invent one.
+     These FKs stay RESTRICT until an explicit deletion-and-retention
+     contract ratifies otherwise.
+4. Workspace-level access is evaluated, not stored here: a grant at any of
+   the three levels evaluates down the chain to workspace-scoped
+   authorization (A1 §8.1.3). No `workspace_id` column exists on
+   `hierarchy_grants` — workspace membership (REQ-ID-001) remains its own
+   mechanism inside the SOT schema, and the chain adds where grants can be
+   declared, never a bypass.
+
+## 4. Ownership and transfer
+
+"Assets are transferable subject to the structure" (PRD Part I §4):
+
+1. A transfer changes exactly one parent FK on exactly one hierarchy row:
+   workspace → new platform-project, platform-project → new estate, estate
+   → new company. Nothing else in the class or the SOT changes: business
+   and orchestration rows inside affected workspaces are untouched, keep
+   their `workspace_id`, and never cross a workspace boundary (A1 §8.1.3
+   "chain maintenance").
+2. Transfer authorization requires authority over BOTH the source and the
+   destination parent. This both-sides predicate is **new policy
+   introduced by this contract pair** (D2/A1 do not state it); its
+   evaluation semantics are contract 2 §5. The structural half — that the
+   transfer command evaluates it before mutating — binds here.
+3. A transfer transaction mutates exactly one class-table row — the
+   single-row parent-FK update — and contains, beyond that, only the
+   §5.2 audit writes for that mutation (the audit event and its
+   hierarchy-outbox record, committing in the same transaction). No other
+   class, business, or orchestration row changes. There are no multi-row
+   transfer batches at the schema level; bulk moves are N audited
+   transfers.
+4. Hierarchy records have no `owner_id`. Ownership in the hierarchy IS the
+   grant structure: a "company owner" is a subject with an `owner` grant
+   on that company or an ancestor (contract 2 §2), not a column. The
+   ownership invariant across the contract pair: a node may hold zero
+   direct owner grants (authority can derive from an ancestor grant); node
+   creation names the initial `owner` grant in the same audited operation
+   and the wizard seeds the first company's owner the same way (contract 2
+   §4.3); transfer and revocation semantics are contract 2 §§5–6. This
+   avoids column-encoded authority of the kind the legacy schema carries
+   (`teams.owner_id` and `teams.manager_id` are required user FKs, and
+   `team_members.role` is a further authority field — none of them
+   evaluable under a grant model).
+
+## 5. Mutation path, audit, and deletion
+
+1. All hierarchy mutations flow through the same sole-writable-SOT,
+   fail-closed, audited Gateway command path as everything else (A1 §8.2.3,
+   REQ-API-001). No direct-DB writers, no raw CRUD endpoints.
+2. **Audit parity.** A1 §8.2 leaves every pre-existing REQ binding, so
+   hierarchy mutations get REQ-AUD-001's guarantees, not a weakened
+   substitute. Concretely:
+   - Every create, rename, transfer, grant create/change/revoke, and
+     delete — including every grant deletion cascaded by a node delete —
+     emits a semantic audit event carrying actor, verb, target, and (for
+     transfers) source and destination parents, with the correlation,
+     causation, idempotency, and per-target ordering guarantees REQ-AUD-001
+     defines.
+   - The state change and its audit event(s) commit in the same
+     transaction, delivered through a transactional outbox. Hierarchy
+     events are not workspace-scoped rows and do not ride the workspace
+     outbox; they get an equivalent hierarchy outbox under the same
+     append-only, same-transaction rules.
+   - **Deletion-safe linkage:** audit events reference their target by an
+     immutable snapshot (id, slug, and parent chain at event time), never
+     by a foreign key into the class tables, so append-only events survive
+     the deletion of their target.
+3. Deletion is fail-closed bottom-up: a hierarchy record with children
+   cannot be deleted (RESTRICT FKs, §2). Deleting a workspace is a SOT-side
+   operation subject to the kanban SOT's own rules and is not granted any
+   new semantics by this contract.
+4. **Roll-up is never a write** (A1 §8.2.2, preserved at full strength). A
+   roll-up read mutates nothing — not hierarchy state, and not business or
+   orchestration state: it must not mutate, claim, order, or gate
+   workspace work. Contract 8 owns projection details but cannot narrow
+   this rule. This contract additionally guarantees the chain roll-ups
+   aggregate over is unique and non-null (§2.5).
+
+## 6. Verification requirements
+
+Binding on the implementing PRs (extends A1 §8.3):
+
+1. Schema witnesses (real PostgreSQL, §6.8): chain construction — insert
+   with a null parent FK refused; insert with one valid parent accepted;
+   two siblings under one parent accepted (the control proving the
+   constraint rejects only what §2.5 forbids); catalog assertion that each
+   child table has exactly one parent-FK column and no parentage edge
+   table exists. Composite slug uniqueness per parent (duplicate slug
+   under same parent refused; same slug under different parents accepted).
+   Grant CHECKs: exactly-one-of subject and exactly-one-of target each
+   witnessed (zero and two set → refused). Grant uniqueness: a duplicate
+   (subject, target, role) row refused for each of the six subject×target
+   forms, proving NULLS-NOT-DISTINCT semantics; NOT NULL on `role`,
+   `granted_by`, and all `name`/`slug` columns witnessed.
+2. Column allowlist: an information_schema assertion that each class
+   table's column set is exactly the set declared in §2/§3 — the bounded
+   observable for no-payload (§2.7) and no-`owner_id` (§4.4).
+3. Command surface: two witnesses, both required (§5.1). (a) Route
+   inventory: an assertion over the Gateway's registered hierarchy
+   routes/commands proving the registered mutation surface is exactly the
+   declared hierarchy command family — no generic CRUD endpoint. (b)
+   Writer coverage — the closed allowlist a route inventory cannot
+   provide: a static CI assertion over the Gateway and package sources
+   with three prongs, each bound to one explicitly enumerated allowlist
+   of hierarchy command/repository modules. (i) Symbol prong: write
+   references to the class-table schema symbols (insert, update, delete)
+   occur only in allowlisted modules. (ii) Literal prong: a class-table
+   name appearing inside a SQL string or tagged SQL template outside the
+   allowlist fails the assertion — this is what catches a raw-SQL writer
+   that references no schema symbol. (iii) Raw-execution prong: any call
+   to a raw-SQL execution primitive (the ORM's raw/unsafe constructors,
+   driver-level query/execute) outside the allowlist fails the
+   assertion, regardless of what the SQL string contains or how it is
+   constructed — the call site is statically detectable even when a
+   dynamically assembled table name is not, so a raw writer with a
+   runtime-built identifier is caught by its primitive, not its
+   payload. Two composition rules keep prong (iii) meaningful: the
+   allowlist names hierarchy command/repository modules only — a
+   generic raw-SQL helper or database-utility module is never
+   allowlisted; and an allowlisted module MUST NOT export a function
+   that executes caller-supplied SQL (such an export is itself a
+   raw-execution primitive, and the exporting module is treated as
+   unallowlisted for prong (iii) if it does). Legitimate raw execution
+   that is not a hierarchy writer — e.g. the migration runner in the
+   db package — lives on a second, separately enumerated
+   **infrastructure register**, distinct from the writer allowlist and
+   equally closed. A registered module is exempt from prong (iii) only:
+   prongs (i) and (ii) apply to it with no exemption, so it can hold no
+   class-table schema symbol or class-table SQL literal, and it can
+   never appear on the writer allowlist. To close the laundering path,
+   the same assertion checks imports, and the import analysis is
+   **re-export-aware**: it follows package barrels and re-exports, so a
+   route hidden behind an index module is still a route — and it
+   resolves literal dynamic imports the same way: an
+   `await import('<literal specifier>')` is an import edge like any
+   static import, not an evasion of the analysis (a dynamic import of
+   the db package whose specifier is not a literal fails the assertion
+   outright, because it makes the import graph unanalyzable). A
+   registered module may be imported only by other registered modules
+   or by importers named on that module's own closed importer
+   enumeration in the register — operational entry points such as the
+   migration/bootstrap CLI or the Gateway's startup migration hook.
+   The enumeration names the complete permitted production consumer
+   set, and completeness is measured, not asserted: the migration
+   runner's measured production importer set today has four members —
+   the Gateway database module (reached through the db package
+   barrel), the storage package's Postgres adapter, and two mosaic CLI
+   commands, the fleet-backlog command and the gateway verify command,
+   both routed through literal dynamic imports of the db package — so
+   its enumeration names those four. A module that only receives the
+   runner's functions by parameter injection (the gateway schema-check
+   module takes them as arguments from the verify command) has no
+   import edge of its own and is not enumerated. Any import route
+   outside the enumeration fails the assertion. Being a
+   named importer confers nothing else: the importer stays fully
+   subject to prongs (i) and (ii), gains no writer-allowlist standing,
+   and whether it uses the registered module beyond its operational
+   purpose is a §5.1 review question, not a static claim. Runtime code-construction
+   primitives (`eval`, `new Function`) anywhere in the scanned sources
+   fail the assertion outright, allowlist or not. Schema definitions
+   and generated migrations are excluded from the literal prong; a
+   false positive is resolved in the same PR by adding the module to
+   the one enumerated list its role permits — the writer allowlist for
+   a hierarchy command/repository module, the infrastructure register
+   for non-hierarchy raw execution — never by weakening the assertion,
+   and neither list may take a module the composition rules bar from
+   it. Both lists are closed, and the assertion's detection
+   claim is exactly its prongs: it statically surfaces every writer
+   expressed as a schema-symbol reference, a class-table SQL literal, a
+   raw-execution call site, or runtime code construction. An evasion
+   engineered outside those syntactic forms is a §5.1 violation that
+   review and audit own — the witness does not claim to catch what
+   static analysis cannot see, and any such evasion found later is
+   corrected as a conformance defect, not grandfathered.
+4. Audit witnesses: for each mutation class (create, rename, transfer,
+   grant create/change/revoke, delete) — the event exists after commit
+   with actor/verb/target and same-transaction atomicity; a rolled-back
+   mutation leaves no event (rollback witness); a node delete's cascaded
+   grant deletions are each covered by events; events survive deletion of
+   their target (query the events of a deleted node).
+5. Transfer tests: parent-FK update moves the subtree resolution and
+   modifies zero business/orchestration rows (row-count and content
+   assertions on workspace contents before/after); transfer without
+   authority on the source or on the destination side is refused (with
+   contract 2 §7.8).
+6. Deletion tests: delete with children refused at the database level;
+   delete of a leaf cascades its grants and nothing else; deleting a user
+   or team that is a grant subject (or `granted_by` referent) is refused
+   (RESTRICT witnesses for §3.3).
+7. Negative tests: no business/orchestration table accepts a company,
+   estate, platform-project, or grant id in any reference position, and
+   none accepts a workspace id in any non-tenancy position; the canonical
+   tenancy FK control — a business row inserted with a valid
+   `workspace_id` succeeds, with an invalid one is refused; roll-up
+   endpoints mutate no canonical state anywhere (assert zero writes across
+   hierarchy AND workspace tables, not hierarchy only); readers see
+   aggregates only over workspaces they are authorized on, with no
+   cross-tenant existence oracles (A1 §8.3 acceptance 3).
+8. Real-PostgreSQL coverage for every constraint witness (unique/CHECK/
+   RESTRICT/NULLS NOT DISTINCT behavior), using the `ci-postgres` service
+   in the `test` CI step; mocked specs cannot witness database constraints.
+
+## Ruling request
+
+Ratify sections 1–6 as written, with one decision embedded: hierarchy
+records carry no owner column — ownership is expressed solely through
+grants (§4.4) — say "agreed" or name the ownership model you want.