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>

docs/architecture/stalker-mock-server.md

@@ -364,7 +364,11 @@ form is the one specs should use.
 webServer: [
   { command: webServerCommand /* web:serve */, url: baseURL },
   {
-    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'],
   },
@@ -374,12 +378,20 @@ webServer: [
 
 Playwright waits for every server to be healthy before starting tests. If one is already running (e.g. in local dev), it reuses the existing instance.
 
+The mock runs as a single `node` process instead of `pnpm nx run
+stalker-mock-server:serve`, because Nx starts its command in a detached
+process group that Playwright's process-group kill never reached, so the server
+outlived the run. The
+[Xtream mock's Playwright section](xtream-mock-server.md#playwright-integration)
+has the details.
+
 **`MOCK_PORT` relocates the whole run.** Playwright's health-check URL and the
 `MOCK_SERVER` constants in the specs read it, and `main.ts` resolves the
 server's port as `PORT`, then `MOCK_PORT`, then `3210` — so
-`MOCK_PORT=3310 pnpm exec playwright test …` starts the Nx-managed mock on
+`MOCK_PORT=3310 pnpm exec playwright test …` starts the mock on
 3310 and points every spec at it, which is how two worktrees run E2E side by
-side when one already holds 3210. This only works because the `serve` and
+side when one already holds 3210. A hand-started Nx mock honours the same
+knobs because the `serve` and
 `serve-with-watch` targets no longer pin `PORT` in `project.json`: an `env`
 entry in `nx:run-commands` overrides the shell (`{...process.env, ...env}`),
 so a pinned value silently discarded every override. `PORT=3310 pnpm nx run

docs/architecture/xtream-mock-server.md

@@ -550,13 +550,37 @@ The mock server is listed as a third `webServer` entry:
 
 ```typescript
 {
-  command: 'pnpm nx run xtream-mock-server:serve',
-  url: 'http://localhost:3211/health',
+  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,
 }
 ```
 
+Every mock-server `webServer` entry uses this launch form, never
+`pnpm nx run …:serve`. The web and Electron E2E configs
+(`apps/web-e2e/playwright.config.ts`,
+`apps/electron-backend-e2e/playwright.config.ts`) start both the Stalker and
+the Xtream mock. The journeys and Xtream benchmark configs start only the
+Xtream mock, on their own loopback ports. The packaged and other performance
+configs start no mock.
+Playwright stops a `webServer` by sending `SIGKILL` to the process group it
+spawned (`taskkill /T /F` on Windows), and Nx `run-commands` starts its command
+in a detached process group of its own. The kill therefore reached only
+`pnpm`/`nx`, and the `tsx` server was reparented and kept the port, which made
+the next run fail with "…/health is already used" or, with
+`reuseExistingServer`, silently reuse a stale server. `node --import tsx` keeps
+the server a single process in Playwright's group. `TSX_TSCONFIG_PATH` stands in
+for the serve target's `--tsconfig` flag and is required for the `@iptvnator/*`
+path aliases. `project-config.spec.ts` pins which configs start which mock,
+and fails if any of them launches a mock through Nx or a new config starts one
+without being listed there. The `serve` targets remain the entry point
+for starting a mock by hand.
+
 ### Request Interception
 
 The Angular PWA calls `localhost:3000/xtream?...`. Playwright intercepts these: