fix(e2e): stop mock servers from outliving Playwright runs (#1710)

* fix(e2e): stop mock servers from outliving Playwright runs

Playwright stops a webServer with a SIGKILL to the process group it
spawned, but `nx run-commands` starts its command in a detached process
group of its own. Launching the Xtream/Stalker mocks through
`pnpm nx run *-mock-server:serve` therefore left the tsx server running
(reparented to PID 1) and holding its port after every run, so the next
run failed with "…/health is already used" or silently reused a stale
server.

Every Playwright config now starts the mocks as a single
`node --import tsx apps/<mock>/src/main.ts` process with
TSX_TSCONFIG_PATH=tsconfig.base.json, which stays in Playwright's group.
A project-config spec guards all playwright*.config.ts files against
regressing to the Nx launch.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* fix(e2e): read sidebar categories atomically; tighten mock launch guard

- category-management: readVisibleSidebarCategoryNames read items one by
  one; when Save removed an item between isVisible() and textContent(),
  textContent() auto-waited for the gone label through the whole 15 s
  poll, so expect.poll never retried (ubuntu shard 1 failed 3/3 while the
  UI already showed "No categories available"). Take one snapshot with
  filter({ visible: true }).evaluateAll() instead.
- project-config.spec: pin which Playwright configs start which mock,
  reject any Nx form that mentions a mock server, and fail when a new
  config starts a mock without being listed (the old count check passed
  vacuously on zero matches).
- docs: state which configs start which mock instead of "every config
  starts both".

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* revert(e2e): leave the sidebar category read race to #1728

#1728 fixes the same readVisibleSidebarCategoryNames race with a shared
helper; keeping a second copy here would only conflict. This PR stays
about mock-server lifecycle.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: 4gray <fourgray@proton.me>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

apps/web-e2e/playwright.config.ts

@@ -66,14 +66,25 @@ export default defineConfig({
             reuseExistingServer: reuseExistingWebServer,
             cwd: workspaceRoot,
         },
+        /* The mocks run as one node process, not through `nx run …:serve`:
+         * Nx starts its command in a detached process group, so Playwright's
+         * process-group kill missed it and the server kept its port. */
         {
-            command: 'pnpm nx run stalker-mock-server:serve',
+            command: 'node --import tsx apps/stalker-mock-server/src/main.ts',
+            env: {
+                NODE_ENV: 'development',
+                TSX_TSCONFIG_PATH: 'tsconfig.base.json',
+            },
             url: `http://localhost:${process.env['MOCK_PORT'] ?? '3210'}/health`,
             reuseExistingServer: !process.env['CI'],
             cwd: workspaceRoot,
         },
         {
-            command: 'pnpm nx run xtream-mock-server:serve',
+            command: 'node --import tsx apps/xtream-mock-server/src/main.ts',
+            env: {
+                NODE_ENV: 'development',
+                TSX_TSCONFIG_PATH: 'tsconfig.base.json',
+            },
             url: `http://localhost:${process.env['XTREAM_MOCK_PORT'] ?? '3211'}/health`,
             reuseExistingServer: !process.env['CI'],
             cwd: workspaceRoot,