feat(agent-reflection): durable kernel — reflection.v1 capture + risk-floor + Phase-0 (#544)

Build the durable kernel of the agent reflection loop. Passive end-of-run
capture of the doer's end-state as structured `reflection.v1` data, plus a
deterministic diff review risk-floor. The closed calibration/skill-synthesis
loop (design §7–§8) stays gated behind Phase-0 experiments P1/P2/P3.

- packages/macp: evaluateRiskFloor (pure, deterministic surface classifier)
  + reflection.v1 JSON Schema; 15 unit tests.
- packages/types: reflection.v1 zod schemas + self-report DTO; 10 unit tests.
- framework: fail-closed Stop hook (reflect-stop-hook.sh) writing the sidecar,
  registered as hooks.Stop in runtime/claude/settings.json. Strict no-op unless
  REFLECTION_MODE=solo|orchestrated; never blocks or fails a session.
- scripts/analysis: P1/P2/P3 experiment harnesses with pre-registered kill
  conditions and structured output.

Mechanical fields (risk, files_changed, ids, provenance) are written by the
hook; self-report fields (confidence, most_likely_wrong, known_not_in_diff) are
merged from an optional $REFLECTION_INPUT, else null + provenance.degraded=true.

Independent review remediations: empty/all-.mosaic diff still writes a sidecar
(grep no-match no longer aborts); session_id sanitized before path use.

Refs #544

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docs/tasks/544-agent-reflection-loop.md

@@ -0,0 +1,67 @@
+# 544: Agent Reflection Loop — durable kernel
+
+**Issue:** [#544](http://git.mosaicstack.dev/mosaicstack/stack/issues/544)
+**PRD:** [`docs/plans/agent-reflection-loop-PRD.md`](../plans/agent-reflection-loop-PRD.md)
+**Branch:** `feat/agent-reflection-loop`
+
+## Context
+
+Build the **durable kernel** of the agent reflection loop: passive end-of-run
+capture of the doer's end-state as structured `reflection.v1` data, plus a
+deterministic diff **review risk-floor**. The closed calibration / skill-synthesis
+loop (design §7–§8) stays **gated** behind Phase-0 experiments P1/P2/P3 and is
+explicitly out of scope here. Source design: jarvis-brain
+`docs/planning/AGENT-REFLECTION-LOOP.md` (debate-hardened v2).
+
+Scope rule, non-goals, the full `reflection.v1` field list, and acceptance
+criteria live in the PRD. This file is the task breakdown + status.
+
+## Work items
+
+| #   | Item                                                  | Path                                                      | Status |
+| --- | ----------------------------------------------------- | --------------------------------------------------------- | ------ |
+| 1   | Diff risk-floor (pure, deterministic) + unit tests    | `packages/macp/src/risk-floor.ts`, `risk-floor.spec.ts`   | done   |
+| 2   | `reflection.v1` JSON Schema (documented contract)     | `packages/macp/src/schemas/reflection.v1.schema.json`     | done   |
+| 3   | `reflection.v1` zod schemas + self-report DTO + tests | `packages/types/src/reflection/*`                         | done   |
+| 4   | Stop hook (fail-closed capture)                       | `packages/mosaic/framework/tools/qa/reflect-stop-hook.sh` | done   |
+| 5   | Hook registration (`hooks.Stop`)                      | `packages/mosaic/framework/runtime/claude/settings.json`  | done   |
+| 6   | Phase-0 experiment harnesses (P1/P2/P3)               | `scripts/analysis/reflect-*.sh`                           | done   |
+
+## Design decisions (this implementation)
+
+- **Mechanical vs self-reported split.** A bash Stop hook cannot author the
+  agent's self-assessment, so it writes the mechanical fields (risk-floor verdict,
+  `files_changed`, ids, provenance) and merges an optional agent-supplied
+  `$REFLECTION_INPUT` self-report; absent/unreadable ⇒ those fields `null` and
+  `provenance.degraded = true`.
+- **Risk-floor authority.** `evaluateRiskFloor` (TS, tested) is the source of
+  truth. The hook ports the same surface table inline to avoid a node/build
+  dependency on the hook path; the two are documented as kept in sync.
+- **Hook registration deviation.** `settings-overlays/` has no merge mechanism
+  (docs-only), so a hooks overlay there would be inert. The Stop hook is
+  registered in the canonical `runtime/claude/settings.json` — the same file the
+  `mosaic` launcher reflects into `~/.claude/settings.json`. Still vendored in-repo.
+- **DTO without class-transformer.** `reflection.dto.ts` uses class-validator only
+  (no `@Type`), matching `chat.dto.ts`, so the module imports without a
+  `reflect-metadata` shim in the types-package test env. Deep nested validation is
+  owned by the zod `ReflectionSelfReportSchema` (the runtime authority the hook uses).
+- **`.mosaic/` excluded** from the change surface — it is agent scratch
+  (reflections, locks, self-report input), not part of the diff under review.
+
+## Verification
+
+- `pnpm --filter @mosaicstack/macp test` → 88 passed (15 new risk-floor).
+- `pnpm --filter @mosaicstack/types test` → 64 passed (10 new reflection).
+- Root `pnpm typecheck`, `pnpm lint`, `pnpm format:check`, `pnpm build` → green.
+- Stop hook smoke: fail-closed no-op (mode unset), solo capture (degraded),
+  self-report merge (degraded=false), re-fire lock guard — all pass.
+- All bash (hook + 3 Phase-0 scripts) shellcheck-clean; Phase-0 scripts emit
+  structured JSON/markdown and print their pre-registered kill conditions.
+
+## Activation (post-merge, deployment concern — not a blocker)
+
+The Stop hook only activates when a launcher/profile sets
+`REFLECTION_MODE=solo|orchestrated`; unset/`off` is a strict no-op, so global
+registration is safe. `framework/install.sh` rsyncs the hook into
+`~/.config/mosaic/tools/qa/`, and the `mosaic` launcher reflects the updated
+`settings.json` (`hooks.Stop`) into `~/.claude/settings.json`.