docs(orchestrator): close out IUV-M01 — mark tasks done, append session 2

Mark all six IUV-01 subtasks as done in docs/TASKS.md with merge commit
pointers, update MISSION-MANIFEST phase to Execution, and append
Session 2 to the install-ux-v2 scratchpad covering the M01 delivery:
PRs #440/#441/#442 merged, mosaic-v0.0.26 tagged and published to the
Gitea npm registry, plus the tsconfig/eslint cross-contamination
learning from the mid-delivery publish pipeline failure.

Refs #436

docs/scratchpads/install-ux-v2-20260405.md

@@ -107,3 +107,42 @@ Sequencing: strict. M01 ships first as a hotfix release (mosaic-v0.0.26). M02 is
 1. Create Gitea issues for M01, M02, M03
 2. Open the mission-scaffold docs PR (same pattern as parent mission's PR #430)
 3. After merge, delegate IUV-M01 to a sonnet subagent in an isolated worktree with the concrete fix-site pointers above
+
+## Session 2 — 2026-04-05 (IUV-M01 delivery + close-out)
+
+### Outcome
+
+IUV-M01 shipped. `mosaic-v0.0.26` released and registry latest confirmed `0.0.26`.
+
+### PRs merged
+
+| PR   | Title                                                                    | Merge    |
+| ---- | ------------------------------------------------------------------------ | -------- |
+| #440 | fix: bootstrap hotfix — DTO erasure, wizard failure, port prefill, copy  | 0ae932ab |
+| #441 | fix: add vitest.config.ts to eslint allowDefaultProject (#440 build fix) | c08aa6fa |
+| #442 | docs: mark IUV-M01 complete — mosaic-v0.0.26 released                    | 78388437 |
+
+### Bugs fixed (all 4 in worker's PR #440)
+
+1. **DTO class erasure** — `apps/gateway/src/admin/bootstrap.controller.ts:16` — dropped `type` from `import { BootstrapSetupDto }`. Guarded by new e2e test `bootstrap.e2e.spec.ts` (4 cases) that binds through a real Nest app with `ValidationPipe { whitelist, forbidNonWhitelisted }`. Test suite needed `unplugin-swc` in `apps/gateway/vitest.config.ts` to emit `decoratorMetadata` (tsx/esbuild can't).
+2. **Wizard silent failure** — `packages/mosaic/src/wizard.ts` — removed the `&& headlessRun` guard so `!bootstrapResult.completed` now aborts in both modes.
+3. **Port prefill** — root cause was clack's `defaultValue` vs `initialValue` semantics (`defaultValue` only fills on empty submit, `initialValue` prefills the buffer). Added an `initialValue` field to `WizardPrompter.text()` interface, threaded through clack and headless prompters, switched `gateway-config.ts` port/url prompts to use it.
+4. **Pi SDK copy** — `packages/mosaic/src/stages/welcome.ts` — intro copy now lists Pi SDK.
+
+### Mid-delivery hiccup — tsconfig/eslint cross-contamination
+
+Worker's initial approach added `vitest.config.ts` to `apps/gateway/tsconfig.json`'s `include` to appease the eslint parser. That broke `pnpm --filter @mosaicstack/gateway build` with TS6059 (`vitest.config.ts` outside `rootDir: "src"`). The publish pipeline on the `#440` merge commit failed.
+
+**Correct fix** (worker's PR #441): leave `tsconfig.json` clean (`include: ["src/**/*"]`) and instead add the file to `allowDefaultProject` in the root `eslint.config.mjs`. This keeps the tsc program strict while letting eslint resolve a parser project for the standalone config file.
+
+**Pattern to remember**: when adding root-level `.ts` config files (vitest, build scripts) to a package with `rootDir: "src"`, the eslint parser project conflict is solved with `allowDefaultProject`, NEVER by widening tsconfig include. I had independently arrived at the same fix on a branch before the worker shipped #441 — deleted the duplicate.
+
+### Residual follow-ups carried forward
+
+1. Headless prompter fallback order: worker set `initialValue > defaultValue` in the headless path. Correct semantic, but any future headless test that explicitly depends on `defaultValue` precedence will need review.
+2. Vitest + SWC decorator metadata pattern is now the blessed approach for NestJS e2e tests in this monorepo. Any other package that adds NestJS e2e tests should mirror `apps/gateway/vitest.config.ts`.
+
+### Next action
+
+- Close out orchestrator doc sync (this commit): mark M01 subtasks done in `TASKS.md`, update manifest phase to Execution, commit scratchpad session 2, PR to main.
+- After merge, delegate IUV-M02 (sonnet, isolated worktree). Dependencies: IUV-02-01 (CORS→FQDN) starts unblocked since M01 is released; first real task for the M02 worker is diagnosing the skill installer failure modes (IUV-02-02) against the fresh 0.0.26 install.