fix(e2e): let per-file E2E targets run without mock serve dependencies (#1772)

* fix(e2e): let per-file E2E targets run without mock serve dependencies

Since #1710 the Playwright configs start the Stalker and Xtream mocks
themselves (`node --import tsx …`), so @nx/playwright can no longer map
those webServers to Nx tasks and infers the atomized `e2e-ci--*` targets
as non-parallel. The `e2e-ci--src/*.e2e.ts` target default still made
them depend on the continuous `stalker-mock-server:serve` and
`xtream-mock-server:serve` targets, and Nx refuses to run a
non-parallel task with continuous dependencies, so every per-file
target failed before running anything.

Drop the redundant mock dependencies and keep the Electron build.
The mock-launch guard spec now also rejects any nx.json target default
that depends on a mock-server task.

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

* test(e2e): scope the mock dependency guard to E2E targets

Check only the `e2e*` target defaults in nx.json, so an unrelated
default may still depend on a mock, and also check every target in the
`apps/*-e2e` project.json files, where a mock `serve` dependency would
break the same targets.

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

* fix(e2e): build Electron only before Electron per-file E2E targets

The `e2e-ci--src/*.e2e.ts` target default also matched web-e2e, so
every browser-only per-file target built electron-backend first. Split
it into project-filtered entries: Electron targets keep `build-e2e`,
web targets get an empty dependency list (which also keeps the
inferred `web:serve` dependency, rejected by Nx on a non-parallel
target, out of them).

The mock dependency guard now also catches `^serve`-style
dependencies, which schedule the mocks through the E2E projects'
implicit dependencies.

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/xtream-mock-server.md

@@ -579,7 +579,11 @@ 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. The web-e2e `web-backend` entry uses the same
+for starting a mock by hand, and no E2E target may depend on them: with no
+Nx-launched server, `@nx/playwright` infers the atomized `e2e-ci--*` targets
+as non-parallel, and Nx refuses to run a non-parallel task that depends on a
+continuous `serve` task. The same spec guards the `e2e*` entries of `nx.json`
+`targetDefaults` and every target in the `apps/*-e2e` `project.json` files. The web-e2e `web-backend` entry uses the same
 launch form; see [PWA web backend](pwa-self-hosted.md#web-backend).
 
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