fix: address round-2 review — stale disconnect, lint-project gap, coverage

Copilot round 2 (PR #2039) surfaced no new visible comments but six
suppressed ones. Four were actionable.

`clients/tui/src/App.tsx` — a stale-completion race in the new banner:
start disconnecting server A, switch to B, then let A's disconnect
reject, and A's failure appears under B. Rapid same-server retries had
the same shape, and the stale attempt is the one most likely to reject.
Claim a monotonic attempt token before awaiting and publish only if it
is still current and the server has not changed; `handleConnect` bumps
the same counter so a connect retires an in-flight disconnect. The
rejection is still owned when superseded — just not published. The
regression test drives a deferred rejection across a server switch, and
fails without the guard.

`tsconfig.lint.json` — the root type-aware block matches
`test-servers/src/**/*.tsx` but the parser project omitted that
extension, so such a file would have failed with "not found in any of
the provided project(s)" instead of being linted. Added, and AGENTS.md
now states the invariant: the include must stay a superset of the lint
globs.

`clients/web/server/{server,vite-hono-plugin}.ts` — the `open()`
rejection branch was untested, and duplicated. Both were fixed by
removing the duplication: `openBrowser` now lives beside
`printServerBanner` in `web-server-config.ts`, with one implementation
to test. Two copies of a one-line `.catch` is two chances for one to
drift back to a bare `open(url)`. The dev plugin is not booted in tests
— it returns early under VITEST by design — but it calls the same
tested helper.

`core/mcp/remote/node/server.ts` — `closeAbortedStream`'s rejecting-close
path, the entire reason the helper exists, had no test. Exported it (as
this file already does for `requestIdForSendWait` / `mcpParamHeadersOnly`)
and covered both legs, asserting no unhandledRejection fires.

Also corrects AGENTS.md, which said each client lists "both" tsconfig
projects — true for cli/tui/launcher, but web lists four leaf projects.

Signed-off-by: cliffhall <cliff@futurescale.com>

AGENTS.md

@@ -723,7 +723,7 @@ The ⚠️ option-deletion hazard, the snapshot rule, and the recovery recipe ab
   - **The class it catches is invisible at review time.** A floated call reads like an awaited one minus four characters, and the unhandled rejection it produces surfaces somewhere else entirely — a different test, a different file, a stack pointing at SDK internals. Two un-held `client.callTool(...)` promises made `npm run ci` unpassable in #1947: `disconnect()` rejected them with `Connection closed`, the unhandled rejection failed the whole vitest run, and the chain aborted at `coverage`, silently skipping `verify:build-gate`, `smoke`, and Storybook. Attributing it took a full investigation; the fix was two lines.
   - **Prefer holding and settling the promise.** `void` is an escape hatch, not a fix — it is visible at review time (strictly better than nothing) but still discards the rejection. Reach for it only when the callee already owns its failures (it ends in a `catch` that surfaces the message) or the caller genuinely cannot await — a synchronous `useEffect` body, an Ink `useInput` key handler, a Hono `stream.onAbort` listener. Say **which** of those it is in a one-line comment; an unexplained `void` is a review finding. Where the callee does *not* own its failures, give it a `catch` rather than voiding the call (see `handleDisconnect` in `clients/tui/src/App.tsx`), or terminate with `.catch(…)` at the call site (see `open(url)` in `clients/web/server/{server,vite-hono-plugin}.ts`).
   - **In Storybook play functions, `expect(...)` from `storybook/test` returns a promise.** Storybook instruments it so the interactions panel can trace each assertion, so every `expect` in a play function is awaited — as is any shared helper that wraps one (`src/test/scrollAreaStoryAssertions.ts` is `async` for this reason).
-  - **The rule is type-aware, so each scope's ESLint config carries a parser project.** The four clients point at their own tsconfig projects (both of them, since `src` and `__tests__`/`server` live in different ones); the root config points at **`tsconfig.lint.json`**, which exists solely to give the parser a program covering `core/**`, `test-servers/src/**`, and `vitest.shared.mts` — none of which is rooted in a tsconfig of its own. That file emits nothing and gates nothing: type *checking* for those sources stays where it was (`core/` through `clients/web`'s `tsc -b`, `test-servers/src` through `clients/cli`'s test project). It sets `moduleResolution: bundler` deliberately — `core/` uses extensionless relative imports, which NodeNext fails to resolve, degrading every import to `any` so the rule silently stops seeing promises at all. **When adding a first-party TS location to the root lint scope, add it to `tsconfig.lint.json`'s `include` too**, or the parser fails it outright with "was not found in any of the provided project(s)". Note also that a tsconfig `include` does **not** expand braces — `core/**/*.{ts,tsx}` matches nothing; list the extensions separately.
+  - **The rule is type-aware, so each scope's ESLint config carries a parser project.** Each client's config must name **every leaf project covering its lint surface**, since the parser needs a program that literally *contains* the file — for cli, tui, and launcher that is the two they already typecheck (`tsconfig.json` + `tsconfig.test.json`, `src` in the first and `__tests__` only in the second), and for **web it is four** (`tsconfig.app.json`, `tsconfig.node.json`, `tsconfig.storybook.json`, `tsconfig.test.json`) — web's `tsconfig.json` is a solution file with `files: []`, so naming it alone would contain nothing. Adding a leaf project to a client means adding it here too. The root config instead points at **`tsconfig.lint.json`**, which exists solely to give the parser a program covering `core/**`, `test-servers/src/**`, and `vitest.shared.mts` — none of which is rooted in a tsconfig of its own. That file emits nothing and gates nothing: type *checking* for those sources stays where it was (`core/` through `clients/web`'s `tsc -b`, `test-servers/src` through `clients/cli`'s test project). It sets `moduleResolution: bundler` deliberately — `core/` uses extensionless relative imports, which NodeNext fails to resolve, degrading every import to `any` so the rule silently stops seeing promises at all. **Its `include` must stay a superset of the root config's type-aware `files` globs** — a file the lint block matches but the project omits fails outright with "was not found in any of the provided project(s)" rather than being checked, so widening one means widening the other (that is why the `include` carries `test-servers/src/**/*.tsx`, which nothing has produced yet). Note also that a tsconfig `include` does **not** expand braces — `core/**/*.{ts,tsx}` matches nothing; list the extensions separately.
   - Type-aware linting costs real time: `clients/web`'s `eslint .` went from ~8s to ~19s, and `lint` runs inside `validate`, the fast inner-loop check. That is the price of the guarantee; if it needs reducing later, narrowing the projects each scope loads is the lever, not dropping the rule.
 
 ## Web source layout: `src/lib` vs `src/utils`