feat(anime): rename NFO Diagnostics to Anime Settings + add edit endpoints

Replaces the read-only 'NFO Diagnostics' page with a full per-anime
Settings page reached from the right-click context menu on series cards.
Users can now view and edit key, name, folder, tmdb_id, tvdb_id and site
for each anime; changes are persisted to the DB and optionally written
back to the NFO file or used to regenerate it.

Backend
- Rename NfoDiagnosticsResponse -> NfoSettingsResponse,
  NfoSeriesDiagnostics -> NfoSeriesSettings
- Rename get_nfo_diagnostics -> get_nfo_settings,
  repair_nfo -> repair_nfo_settings
- Fix nfo.py bug: repair was calling non-existent
  update_series_nfo_status(); now uses update_nfo_status() and an
  explicit AnimeSeriesService.update(nfo_path=...)
- New endpoints on /api/anime/{key}:
    GET  /settings            -> AnimeSettingsResponse
    PUT  /settings            -> AnimeSettingsResponse
                                 (body: name/folder/tmdb_id/tvdb_id/site,
                                  options: apply_to_nfo, rename_disk)
    POST /regenerate-nfo      -> AnimeSettingsRegenerateNfoResponse
- New Pydantic models: AnimeSettingsResponse,
  AnimeSettingsUpdateRequest, AnimeSettingsRegenerateNfoResponse
- /anime/settings page route; /settings/nfo now 301-redirects to it

Frontend
- New AniWorld.AnimeSettingsManager JS module (single-page form,
  no tabs) with public API init/loadSeries/saveSettings/regenerateNfo/
  validateField/populateForm/showSaveSuccess/showError
- New anime-settings.html template + anime-settings.css
- Right-click menu: data-action 'nfo-diagnostics' replaced by
  'anime-settings' (label 'Anime Settings'), navigates to
  /anime/settings?key=...
- Library 'Open NFO Diagnostics' link renamed to 'Open Anime Settings'

Bug fix
- context-menu click handler was calling hide() BEFORE building the
  navigation URL, which cleared currentSeriesKey to null and produced
  /anime/settings?key=null. Captures the key into a local const first.
  Regression-locked by tests/frontend/unit/context_menu.test.js.

Tests
- 21 new pytest tests in tests/api/test_anime_settings_endpoints.py
  (GET/PUT/regenerate-nfo, auth, validation, nfo-repair bug regression)
- tests/api/test_nfo_endpoints.py trimmed to 6 focused tests
- 31 new Vitest unit tests for AnimeSettingsManager
- 5 new Vitest unit tests for ContextMenu (incl. source-invariant
  regression guard for the hide()-before-key bug)
- 5 new Playwright E2E tests covering right-click, direct nav,
  legacy /settings/nfo redirect, and context-menu labels
- New vitest.config.js (environment: happy-dom)

Docs
- Docs/API.md: new section 'Anime Settings Endpoints'
- Docs/CHANGELOG.md: documents the rename and the context-menu bug fix

Verified
- pytest: 27/27 (21 new + 6 trimmed nfo)
- vitest: 36/36 (31 anime-settings + 5 context-menu)
- playwright e2e: 5/5

Docs/CHANGELOG.md

@@ -37,6 +37,72 @@ This changelog follows [Keep a Changelog](https://keepachangelog.com/) principle
 
 ---
 
+## [Unreleased] - 2026-06-20
+
+### Added
+
+- **Anime Settings page** — renamed from "NFO Diagnostics". Right-click
+  on any anime card → "Anime Settings" navigates to
+  `/anime/settings?key=<series>`. The new page lets the user view and
+  edit `name`, `folder`, `tmdb_id`, `tvdb_id`, and `site` directly in
+  the database, with options to rename the on-disk folder and
+  regenerate `tvshow.nfo` in one click.
+- **New API endpoints** under `/api/anime/{key}/`:
+    - `GET  /settings` — return full editable settings payload
+    - `PUT  /settings` — update fields with validation
+    - `POST /regenerate-nfo` — regenerate `tvshow.nfo` from TMDB
+- **Pydantic models**: `AnimeSettingsResponse`,
+  `AnimeSettingsUpdateRequest`, `AnimeSettingsRegenerateNfoResponse`
+  in [src/server/models/anime.py](../src/server/models/anime.py).
+- **Frontend module**: `AniWorld.AnimeSettingsManager` IIFE in
+  [src/server/web/static/js/pages/anime-settings.js](../src/server/web/static/js/pages/anime-settings.js)
+  with public API: `init`, `loadSeries`, `saveSettings`,
+  `regenerateNfo`, `validateField`, `populateForm`, `showSaveSuccess`,
+  `showError`.
+- **Vitest JS unit tests** covering every public function on
+  `AnimeSettingsManager` — 31 tests in
+  [tests/frontend/unit/anime_settings.test.js](../tests/frontend/unit/anime_settings.test.js).
+- **Playwright E2E test** for the right-click → settings page flow in
+  [tests/frontend/e2e/anime_settings_page.spec.js](../tests/frontend/e2e/anime_settings_page.spec.js).
+
+### Changed
+
+- **Right-click context menu** on the library page: "NFO Diagnostics"
+  → "Anime Settings" (`data-action="nfo-diagnostics"` →
+  `data-action="anime-settings"`).
+- **Configuration modal link**: "Open NFO Diagnostics" → "Open Anime
+  Settings", target URL `/settings/nfo` → `/anime/settings`.
+- **Page route**: `/settings/nfo` returns a 301 redirect to
+  `/anime/settings` for backwards compatibility with bookmarks.
+- **Pydantic model rename** in [src/server/models/nfo.py](../src/server/models/nfo.py):
+    - `NfoDiagnosticsResponse` → `NfoSettingsResponse`
+    - `NfoSeriesDiagnostics` → `NfoSeriesSettings`
+- **Function rename** in [src/server/api/nfo.py](../src/server/api/nfo.py):
+    - `get_nfo_diagnostics` → `get_nfo_settings`
+    - `repair_nfo` → `repair_nfo_settings`
+
+### Fixed
+
+- **Bug**: `src/server/api/nfo.py` called the non-existent
+  `anime_service.update_series_nfo_status(...)` method, which would
+  raise `AttributeError` after a successful NFO repair. Renamed the
+  call to the existing `update_nfo_status(...)` method (matching its
+  signature `(key, has_nfo, tmdb_id=None, tvdb_id=None, db=None)`)
+  and added an explicit `AnimeSeriesService.update(db, id, nfo_path=...)`
+  call to keep `nfo_path` in sync. Covered by regression tests in
+  `TestBugFixCreateOrUpdateNfo`.
+
+- **Bug**: Right-clicking a series card and choosing "Anime Settings"
+  opened `/anime/settings?key=null` instead of carrying the series key.
+  Root cause: the click handler in
+  [src/server/web/static/js/index/context-menu.js](../src/server/web/static/js/index/context-menu.js)
+  called `hide()` BEFORE building the URL — and `hide()` cleared
+  `currentSeriesKey` to null. Fix captures the key into a local
+  `const` before calling `hide()`. Regression-locked by
+  `tests/frontend/unit/context_menu.test.js` (5 tests).
+
+---
+
 ## [Unreleased] - 2026-06-05
 
 ### Fixed