chore: close quality-gate coverage gaps (#1689) (#1766)

Closes #1689. Typecheck cli/tui src, add a core/ format+lint gate, and gate core/json + core/client coverage. See PR #1766 for the full review history.

AGENTS.md

@@ -194,7 +194,7 @@ gh project item-edit --project-id PVT_kwDOCt2Azc4BJVxt --id "$ITEM_ID" --field-i
 - Run TUI tests with `npm run test` from `clients/tui/`
 - The repo root has no aggregate `test` script — each client self-validates, so run `npm run validate` from the root (all clients, fast) or `cd clients/<name> && npm run validate` (one client). Each client still exposes its own `test` / `test:coverage` for quick iteration.
 - **`validate` is fast: it runs `test`, not `test:coverage`.** The coverage gate (slower — adds v8 instrumentation, and for web the integration project) is a **separate** top-level `npm run coverage` (and per-client `coverage:web` / `coverage:cli` / `coverage:tui` / `coverage:launcher`, each delegating to that client's `test:coverage`). Run `npm run coverage` when you want to reproduce the gate locally before pushing. **CI runs `coverage`** on every push (#1550): the per-file ≥90 gate is CI-enforced, so a PR that drops any file below 90 on lines/statements/functions/branches fails the job. CI runs `validate` (fast) for format/lint/build/unit tests, then `coverage` for the instrumented gate. Because web's `test:coverage` already runs the integration project, CI has no separate `test:integration` step — the integration paths are exercised inside the coverage gate.
-- Each client's `test:coverage` enforces a **uniform per-file gate of ≥ 90 on all four dimensions** — lines, statements, functions, and branches — across `clients/web`, `clients/cli`, `clients/tui`, and `clients/launcher` (CI enforces this gate). This is the result of a codebase-wide audit: the branch floor was first lifted 50 → 70 for web (#1271), then the whole gate raised to 90 with real tests added for every outlier. Genuinely-unreachable branches are **not** waved through by lowering the gate — they are annotated at the source with a justified `/* v8 ignore … -- <reason> */` comment. Acceptable reasons are happy-dom-inherent paths (Mantine portal mount points, `useMediaQuery` fallbacks, `typeof window` SSR guards), React StrictMode effect-replay blocks, and provably-dead defensive guards (e.g. a `?? fallback` for a value the types guarantee non-null, or a `Select.onChange` receiving a value outside the allowed list). New code must clear 90 on every dimension; reach for a justified `v8 ignore` only when a branch is genuinely impossible to exercise.
+- Each client's `test:coverage` enforces a **uniform per-file gate of ≥ 90 on all four dimensions** — lines, statements, functions, and branches — across `clients/web`, `clients/cli`, `clients/tui`, and `clients/launcher` (CI enforces this gate). This is the result of a codebase-wide audit: the branch floor was first lifted 50 → 70 for web (#1271), then the whole gate raised to 90 with real tests added for every outlier. Genuinely-unreachable branches are **not** waved through by lowering the gate — they are annotated at the source with a justified `/* v8 ignore … -- <reason> */` comment. Acceptable reasons are happy-dom-inherent paths (Mantine portal mount points, `useMediaQuery` fallbacks, `typeof window` SSR guards), React StrictMode effect-replay blocks, and provably-dead defensive guards (e.g. a `?? fallback` for a value the types guarantee non-null, or a `Select.onChange` receiving a value outside the allowed list). New code must clear 90 on every dimension; reach for a justified `v8 ignore` only when a branch is genuinely impossible to exercise. The web coverage `include` (in `clients/web/vite.config.ts`) covers the shared `core/` runtime consumed by the browser — `core/mcp`, `core/react`, `core/auth`, `core/storage`, `core/logging`, `core/node`, **`core/json`, and `core/client`** (the last two folded in by #1689). When adding a `core/json/*` or `core/client/*` module, its tests live under `clients/web/src/test/core/…` and are gated the same ≥90 way.
 - The **same per-file gate** is enforced for the CLI and TUI (#1484), not just web:
   - **CLI** (`clients/cli`): tests run **in-process** by importing `runCli()` (see `__tests__/helpers/cli-runner.ts`) so `clients/cli/src` is measured under v8 instrumentation. A thin out-of-process layer (`__tests__/e2e.test.ts` + `scripts/smoke-cli.mjs`) still spawns the built binary for the shebang/`process.exit` paths; `src/index.ts` (binary bootstrap) is the only coverage exclusion. `commander` uses `.exitOverride()` so a parse error throws instead of tearing down the test worker.
   - **TUI** (`clients/tui`): the gate covers the **non-React logic** only — `logger.ts`, `components/tabsConfig.ts`, and `utils/*` (server resolution lives in `core/` and is measured by the web suite). The Ink components, `App.tsx`, and `hooks/` are an **interim exclusion** in `clients/tui/vitest.config.ts` pending the renderer-based follow-up (#1501). When adding new **non-React** logic under `clients/tui/src`, it falls under the gate automatically — add tests for it.
@@ -209,10 +209,12 @@ gh project item-edit --project-id PVT_kwDOCt2Azc4BJVxt --id "$ITEM_ID" --field-i
   - after making the changes, respond to each review comment with what was done (or why it was ignored)
 
 ### Mandatory pre-push gate
-- ALWAYS do `npm run format` before committing — it auto-fixes any Prettier issues. `validate` runs `format:check` (the non-fixing variant) and will fail in CI on any unformatted file, so always run the auto-fixer first rather than letting `format:check` catch it.
+- ALWAYS do `npm run format` before committing — the **root** `format` auto-fixes `core/` (`format:core`) and every client's scope in one shot. `validate` runs `format:check` (the non-fixing variant, including `format:check:core`) and will fail in CI on any unformatted file, so always run the auto-fixer first rather than letting `format:check` catch it.
 - **`npm run ci` is the mandatory pre-push command** — it mirrors `.github/workflows/main.yml` (minus `npm install`): `validate` → `coverage` → `smoke` → Storybook play-function tests (installs Playwright chromium if needed). It now runs **`npm run coverage`**, the per-file ≥90 gate (lines/statements/functions/branches) that CI enforces — so `npm run ci` is a true superset of GitHub CI, and passing it locally means CI's gates will pass. Expect several minutes. **`npm run validate`** remains the fast inner-loop check during development (unit tests only — no coverage gate, no smoke, no Storybook), but it is **NOT** an acceptable substitute for `npm run ci` before pushing: `validate` runs `test`, not `test:coverage`, so it does **zero** coverage gating. Skipping the gate is how a push passes every fast local check and still fails CI (this exact gap broke PR #1601 on a function-coverage regression).
-- ALWAYS do `npm run format` before committing, then **`npm run ci`** before pushing. From the repo root, `validate` chains the four per-client validations (`validate:web` → `validate:cli` → `validate:tui` → `validate:launcher`); each delegates to that client's own `npm run validate` = `format:check` + `lint` + `build` + `test` in its own folder (no coverage — fast). Every client is self-validating and the top level just chains them, building each client's bundle along the way (no cross-client build dependencies).
-  - The one CLI nuance: `clients/cli`'s out-of-process `e2e.test.ts` spawns the built binary, so its `test` **builds first** via `pretest` (`test-servers:build && build`). To avoid building it twice, `clients/cli`'s `validate` folds that in — it is `format:check && lint && test` with **no** separate `build` step (the other clients, whose tests don't spawn their bundle, keep an explicit `build`). `validate:web`/`validate:tui`/`validate:launcher` are the uniform `format:check && lint && build && test`.
+- ALWAYS do `npm run format` before committing, then **`npm run ci`** before pushing. From the repo root, `validate` runs the **`core/` gate first** (`validate:core`) and then chains the four per-client validations (`validate:web` → `validate:cli` → `validate:tui` → `validate:launcher`); each client delegates to its own `npm run validate` in its own folder (no coverage — fast). Every client is self-validating and the top level just chains them, building each client's bundle along the way (no cross-client build dependencies).
+  - **`validate:core` is the shared-code format + lint gate (#1689).** Each client's `prettier`/`eslint` is scoped to its own dir, so nothing reached `core/` before — `validate:core` closes that: it runs `format:check:core` (`prettier --check "core/**/*.{ts,tsx}"`) + `lint:core` (`eslint "core/**/*.{ts,tsx}"` via the **root** `eslint.config.js`). Use `npm run format:core` to auto-fix. The root carries prettier/eslint as devDependencies for this; `core/` is isomorphic (browser + Node globals, no JSX today — the `{ts,tsx}` glob future-proofs against a `core/**/*.tsx`). The root `eslint.config.js` honors an `_`-prefix as the intentionally-unused marker (`argsIgnorePattern`/`varsIgnorePattern`/`caughtErrorsIgnorePattern: '^_'`).
+  - **cli and tui now typecheck their `src` (#1689).** Their `build`/`test` run through esbuild (no type check), so each has a `typecheck` script (`tsc --noEmit -p tsconfig.json`) folded into `validate`. Their `tsconfig.json` matches `clients/web/tsconfig.app.json`'s module/lib *resolution* options — DOM lib, `moduleResolution: bundler`, and **no** `noUncheckedIndexedAccess` (web's app config does not extend `tsconfig.base`, so re-enabling it would surface `core/` issues web never gates) — so the imported `core/` sources are validated the same way web validates them. It does **not** mirror web's extra strictness flags (`noUnusedLocals`, `verbatimModuleSyntax`, ES2023 target, …), so cli/tui's own `src` is checked slightly more loosely than web's. `core/` itself still typechecks through web's `tsc -b`.
+  - The one CLI nuance: `clients/cli`'s out-of-process `e2e.test.ts` spawns the built binary, so its `test` **builds first** via `pretest` (`test-servers:build && build`). To avoid building it twice, `clients/cli`'s `validate` folds that in — it is `format:check && lint && typecheck && test` with **no** separate `build` step (the other clients, whose tests don't spawn their bundle, keep an explicit `build`). `validate:web`/`validate:tui`/`validate:launcher` are the uniform `format:check && lint && (typecheck &&) build && test`.
   - **`npm run coverage`** is the per-file ≥90 gate and is now part of `npm run ci` — never treat it as optional before a push. It supersedes the old standalone `test:integration` step: web's `test:coverage` runs the `unit` **and** `integration` projects under v8 instrumentation, so `coverage` both enforces the ≥90 gate and exercises the same web integration paths CI covers.
 - **`smoke` is NOT part of `validate`** — it is included in `npm run ci`. It runs `smoke:launcher` (`--help` dispatch) plus the prod `smoke:cli` / `smoke:tui` / `smoke:web`, and contains **no build commands** — it assumes the cli/tui/launcher bundles already exist (a full `validate` builds them; `smoke:web` builds `clients/web/dist` on demand). CI runs `validate`, then the `coverage` gate (which also covers the web integration project), then `smoke`. Storybook is the only CI step left out (see below).
 - `smoke:launcher` (`scripts/smoke-launcher.mjs`) runs the built launcher with `--help`, `--cli --help`, and `--tui --help`, asserting each exits 0 and prints that mode's usage banner (which also proves the launcher resolved and loaded the right client build). It's the cheap dispatch check before the heavier prod smokes below.