fix(proxy): proxy /api/fetch, and detect entry-inlined externals

Addresses the Copilot review on #2099.

- `/api/fetch` used the bare global `fetch`. That route is the browser's only
  way out to the network — the web client's `environment.fetch` is
  `createRemoteFetch()`, which forwards OAuth discovery and token requests
  there — so a corporate-proxy user could connect to a server but never
  authorize against it, and the PR's "OAuth is proxied now" claim held for the
  CLI and TUI but not for web. It now uses the same proxy-aware base fetch, with
  an integration test driving a real forwarding proxy (confirmed failing without
  the fix).

- `verify:bundle-externals` only recognized an inlining that produced a
  `<pkg>-HASH.js` chunk. A *statically* imported package is folded into
  `index.js` and emits no chunk, so it would have passed. Detection now keys off
  esbuild's `// <path>` module banners, covering both shapes. Because that
  depends on unminified output, a bundle with no banners now fails as such
  rather than reporting clean — enabling `minify` cannot silently retire the
  check. Tests cover the entry-inlined case, the same-prefix case
  (`undici-types` must not read as `undici`), and the no-banner case.

- The pre-push pipeline summaries in AGENTS.md, README.md, and
  .github/copilot-instructions.md still described `verify:build-gate → smoke`
  and omitted the new gate.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JTHVxSu8AUgHRLvo1ntZ8H
Signed-off-by: cliffhall <cliff@futurescale.com>

.github/copilot-instructions.md

@@ -101,7 +101,7 @@ Both exist and do different jobs. Theme files (`src/theme/<Component>.ts`) custo
 
 ## Gates and PR hygiene
 
-- `npm run format` before committing; **`npm run ci` before pushing** (`validate` → `coverage` → `verify:build-gate` → `smoke` → Storybook). `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.
+- `npm run format` before committing; **`npm run ci` before pushing** (`validate` → `coverage` → `verify:build-gate` → `verify:bundle-externals` → `smoke` → Storybook). `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`. 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.
 - **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_.