perf(web): make the app root and settings components OnPush (#1823)

* perf(web): make the app root and settings components OnPush

Plan item C6 step 3 for apps/web: the fifteen Eager components switch to
OnPush, among them the app root and the update notification panel that
the idle audit found re-rendering on every idle tick. Their template
state is signals from the settings facades, signal inputs and the shared
reactive settings form.

The checklist flagged the backup import, which patches the form from a
detached file input with no template event. A new spec patches only a
value, which changes no form status, and confirms the OnPush general
section still shows the new theme; it guards that path for the zoneless
flag.

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

* fix(settings): re-render OnPush sections when the form changes outside them

Review follow-ups (Greptile, Codex):

- The settings sections read form values in their templates (selected
  theme and cover size, epgField.value, form().value.player), and the
  parent changes the form outside their events: Discard and backup import
  patch it, the store hydrates it, the EPG file picker sets a control
  after an await. Under OnPush the section kept the old selection or EPG
  status. Each section now marks itself on its form's events
  (markSectionForCheckOnFormEvents).
- The value-only patch test no longer forces detectChanges(); with the
  fixture rendering on its own it fails without the marking, and so does
  a new test for a control set outside the EPG section.
- The zoneless guard counts only changeDetection metadata outside
  comments, so a comment naming the strategy is not an Eager component.

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

* test(settings): guard the unsaved-changes bar after a save off the sections

Review follow-up (Codex): Save marks the form pristine after an async
store write, also on Backup, Reset or search, where no form section is
rendered. The OnPush page re-renders anyway because pristine and valid
read the form's state signals; the new test checks that on the Backup
page without forcing a render (it waits for the scheduled one).

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/zoneless-migration.md

@@ -63,25 +63,30 @@ must be ticked here.
 two). Tick an entry by deleting `changeDetection: ChangeDetectionStrategy.Eager`
 (or setting OnPush) once its template state is signals, signal inputs or
 explicitly marked. The guard spec compares the unticked entries with the
-files that still contain `ChangeDetectionStrategy.Eager`.
+files whose component metadata still sets
+`changeDetection: ChangeDetectionStrategy.Eager` (comments do not count).
+The settings sections read form values in their templates and the parent
+patches the form outside their events (Discard, backup import, the EPG file
+picker), so each marks itself on the form's `events` through
+`markSectionForCheckOnFormEvents` (`apps/web/src/app/settings`).
 
 ### apps/web (15)
 
-- [ ] `apps/web/src/app/app.component.ts` (idle audit root)
-- [ ] `apps/web/src/app/app-update-notification-panel.component.ts` (idle audit root)
-- [ ] `apps/web/src/app/settings/app-update-release-notes-dialog.component.ts`
-- [ ] `apps/web/src/app/settings/settings.component.ts`
-- [ ] `apps/web/src/app/settings/settings-about-section.component.ts`
-- [ ] `apps/web/src/app/settings/settings-backup-section.component.ts`
-- [ ] `apps/web/src/app/settings/settings-dashboard-section.component.ts`
-- [ ] `apps/web/src/app/settings/settings-delete-all-playlists-dialog.component.ts`
-- [ ] `apps/web/src/app/settings/settings-epg-section.component.ts`
-- [ ] `apps/web/src/app/settings/settings-general-section.component.ts`
-- [ ] `apps/web/src/app/settings/settings-playback-section.component.ts`
-- [ ] `apps/web/src/app/settings/settings-remote-control-section.component.ts`
-- [ ] `apps/web/src/app/settings/settings-reset-section.component.ts`
-- [ ] `apps/web/src/app/settings/settings-tmdb-section.component.ts`
-- [ ] `apps/web/src/app/settings/settings-unsaved-changes-dialog.component.ts`
+- [x] `apps/web/src/app/app.component.ts` (idle audit root)
+- [x] `apps/web/src/app/app-update-notification-panel.component.ts` (idle audit root)
+- [x] `apps/web/src/app/settings/app-update-release-notes-dialog.component.ts`
+- [x] `apps/web/src/app/settings/settings.component.ts`
+- [x] `apps/web/src/app/settings/settings-about-section.component.ts`
+- [x] `apps/web/src/app/settings/settings-backup-section.component.ts`
+- [x] `apps/web/src/app/settings/settings-dashboard-section.component.ts`
+- [x] `apps/web/src/app/settings/settings-delete-all-playlists-dialog.component.ts`
+- [x] `apps/web/src/app/settings/settings-epg-section.component.ts`
+- [x] `apps/web/src/app/settings/settings-general-section.component.ts`
+- [x] `apps/web/src/app/settings/settings-playback-section.component.ts`
+- [x] `apps/web/src/app/settings/settings-remote-control-section.component.ts`
+- [x] `apps/web/src/app/settings/settings-reset-section.component.ts`
+- [x] `apps/web/src/app/settings/settings-tmdb-section.component.ts`
+- [x] `apps/web/src/app/settings/settings-unsaved-changes-dialog.component.ts`
 
 ### libs/ui (20 files, 21 components)
 
@@ -176,7 +181,7 @@ the field a signal (or a `computed`), or writes it through one.
 | [ ] | `libs/portal/stalker/feature/src/lib/stalker-live-stream-layout/stalker-live-stream-layout.component.ts` (favorites load) | `favorites` Map filled in a `subscribe` without `markForCheck`; the component is OnPush already, so this is a latent bug today | portal |
 | [ ] | `libs/portal/xtream/feature/src/lib/portal-channels-list/portal-channels-list.component.ts` (favorites load) | same pattern; the neighbouring `favoriteMarks.changes$` handler does call `markForCheck` | portal |
 | [ ] | same file, programme dialog `afterClosed` | deletes from `epgPrograms`/`currentProgramsProgress` after `await` without marking | portal |
-| [ ] | `apps/web/src/app/settings/settings-backup.facade.ts` (backup import) | `change` listener on a detached file input → `hydrateFromStore()`; section templates read `form().value.theme`/`coverSize` | apps/web |
+| [x] | `apps/web/src/app/settings/settings-backup.facade.ts` (backup import) | `change` listener on a detached file input → `hydrateFromStore()`; section templates read `form().value.theme`/`coverSize`; no fix needed: a value-only `patchValue` re-renders the OnPush sections (`settings.component.form.spec.ts` guards it) | apps/web |
 | [ ] | `libs/ui/remote-control/src/lib/remote-control/remote-control.component.ts` | plain `isLoading`/`error`/`status` written after `await` and from a 2 s `setInterval` | only if `apps/remote-control-web` goes zoneless |
 
 ## Explicit zone and change-detector calls
@@ -185,7 +190,7 @@ They keep working under zoneless (`NgZone` becomes `NoopNgZone`, so `run`
 and `runOutsideAngular` just call through). Remove them in the flip PR, not
 before: with zone.js on they still matter.
 
-- [ ] `apps/web/src/app/settings/settings-unload-guard.service.ts`: two
+- [x] `apps/web/src/app/settings/settings-unload-guard.service.ts`: two
   `zone.run` calls around the window-close dialog (IPC
   `onWindowCloseRequested` and `beforeunload`).
 - [x] `libs/ui/playback/src/lib/embedded-mpv-player/embedded-mpv-session-controller.ts`: