Merge branch 'v2/main' into v2/chore/2159-parallel-coverage-job

.github/copilot-instructions.md

@@ -105,6 +105,7 @@ Both exist and do different jobs. Theme files (`src/theme/<Component>.ts`) custo
 - `npm run format` before committing; **`npm run ci` before pushing** (`validate` → `coverage` → `verify:build-gate` → `verify:bundle-externals` → `smoke` → `smoke:web:firefox` → Storybook; the Firefox step is local-only and not mirrored in GitHub CI). `npm run validate` is the fast inner-loop check and is **not** a substitute — it runs `test`, not `test:coverage`, so it does zero coverage gating.
 - **A dependency bump must land in every install that declares it.** v2 is not a workspace — the root and each `clients/*` have their own `node_modules`, and a client's test project compiles `core/` and `test-servers/src` (which resolve from the **root**) alongside the client's own sources. Bumping a shared dependency in one manifest only puts two versions of it in one `tsc` program; for a recursive-generic surface like zod that exhausts the tsc heap (#1896). `verify:dep-lockstep` fails the build on this — it derives its candidates from what each `tsc` program actually resolves (`tsc --listFilesOnly`, keeping packages that reach one program from two installs), so a package reached only through another package's `.d.ts` counts too (#1965) — so a PR bumping a package the shared sources pull in should update the root **and every client that already lists it** — not every client unconditionally, since a package absent from an install can't skew and adding it there would be a spurious dependency.
 - **A test or smoke must not touch real user state.** The web smokes run against a throwaway catalog via the shared `scripts/lib/prod-web-server.mjs` helper, never the developer's `~/.mcp-inspector/mcp.json` (#1977); the cli/tui smokes drive a temp `--catalog`; `pack:verify`'s `--web` child sets its own `MCP_CATALOG_PATH` for the same reason (#2003 — its App deep link persists a server row). Anything that boots the web backend and then *navigates* it needs that isolation, not just the scripts named `smoke:*`. A new smoke spawning its own server, or teardown that removes a work dir without first awaiting `stopChild` (the #1801 race — `child-cleanup.mjs` exports both halves and both are required), should be flagged.
+- **A smoke must assert the thing survives, not that it started.** `smoke:tui` runs the Ink TUI under a pseudoterminal (`scripts/lib/pty.mjs`) and requires it to still be running `SMOKE_TUI_SURVIVE_MS` after its first frame (`scripts/lib/render-smoke.mjs`) — because it previously settled OK on first paint while the TUI was exiting 1 ~40ms later with `Raw mode is not supported`, and won that race on every machine (#2147). Flag anything that collapses the survival wait back into "resolve on the marker", and any new smoke whose only assertion is that a process printed something once. A smoke walks only its own happy path, so the branch that matters — started, then died — belongs in a `scripts/lib/*.test.mjs` driven against a stub (as with `announced-child.mjs` #2000 and `ensure-test-servers.mjs` #2111), not in the smoke.
 - **The headless web smokes are engine-parameterized, not Chromium-only.** `smoke:web:browser` / `smoke:web:app` / `smoke:web:elicit` take their engine from `SMOKE_BROWSER` (chromium — the default — firefox, webkit). **GitHub CI runs Chromium only; Firefox runs in the local pre-push gate** via `smoke:web:firefox` (#2086 — a CI job was trialled and removed for never disagreeing with Chromium across a dozen runs, and moved into `npm run ci` instead). They exist because the MCP Apps sandbox is built out of the primitives that diverge between engines: `srcdoc` CSP inheritance, nested sandboxed iframes, `Permissions-Policy`, cross-frame `postMessage`. Nothing else covers that — `sandbox-csp.test.ts` asserts a policy *string*, and no Storybook story reaches the sandbox at all. Flag a new browser-driven script that launches Playwright itself instead of going through `scripts/lib/headless-browser.mjs`, an unrecognized-engine path that falls back to Chromium rather than failing (it would claim coverage that never ran), or a launch-failure message naming the wrong engine. `pack:verify` is pinned to Chromium on purpose — it is a packaging check.
 
 - **Build output is never a gate target.** Lint, format, and typecheck read first-party source only; everything a build writes (`clients/*/build`, `clients/web/dist`, `storybook-static`, `coverage`, `test-servers/build`, `core/**/{build,dist}`, `*.tsbuildinfo`) stays out via each scope's `globalIgnores`, `format` globs, and tsconfig `include`. Gating generated code reports defects in vendored third-party source that nobody can fix, and a rule promotion turns that warning into a `validate` failure (#2043). Flag a PR that adds a build location without ignoring it in the same change, that widens an ignore to silence a finding in first-party code, or that adds a build directory to a tsconfig `include` to make a generated `.d.ts` resolve. Note the coverage guards don't catch this — they assert source is _covered_, not that output is _excluded_.