feat(transmission): add Transmission torrent client integration

CHANGELOG.md

@@ -17,6 +17,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Internal
 - **CI / release workflows modernised.** Bumped the pinned GitHub Actions to current majors (`checkout@v5`, `setup-qemu@v4`, `setup-buildx@v4`, `login@v4`, `metadata@v6`, `build-push@v7`, `dockerhub-description@v5`, `action-gh-release@v3`) across `ci`, `beta`, `release` and `dockerhub-readme`, added a `workflow_dispatch` trigger to `ci` so the suite can be run on demand, and guarded the Docker Hub README sync with `if: github.repository == 'Shoshuo/Prismarr'` so forks don't fail the job on missing secrets.
 ### Added
+- **Transmission torrent client integration.** A new download-client page (setup wizard step, admin settings entry, sidebar badge/poll, health circuit breaker) alongside qBittorrent, modeled on the same conventions. Transmission's RPC session handshake is handled transparently: the first request without a valid `X-Transmission-Session-Id` gets an expected HTTP 409 carrying the real token, which the client caches and retries with — the setup wizard's Test button and the dashboard health check both treat that 409 as "reachable," while a genuine `401` (bad RPC password) is reported as an auth failure. The user/password fields are optional, matching qBittorrent's reverse-proxy-friendly config shape. The page covers the list/table/compact torrent views, filtering, search, sort, pagination, bulk actions (pause/resume/delete/recheck, plus pause-all/resume-all), a per-torrent detail modal (general/files/trackers/peers) and add-by-URL / add-by-file, with a read-only category filter derived from Transmission's own labels.
 - **Plex activity via Tautulli (optional).** A new read-only Tautulli integration (URL + API key in `/admin/settings`, behind the per-service health circuit breaker) surfaces current Plex activity. The dashboard gets a "Current Plex activity" widget — active streams, Direct Play / Direct Stream / Transcode counts, total / LAN / WAN bandwidth and a per-session card (quality, HDR/SDR badge, source→target codec when transcoding) — that hydrates on its own and refreshes every 10 s. A dedicated **Plex Activity** page (own sidebar entry) adds a now-playing strip, watch statistics with a 7 / 30 / 90-day toggle (top movies / shows / users / platforms), plays-over-time graphs with a Media-type ⇄ Stream-type toggle plus by-hour and by-day-of-week breakdowns and a platform × stream-type "problem clients" chart, a dense watch-history grid, and per-library item counts. Each title opens an in-app info modal (synopsis, ratings, cast/crew). The API key never leaves the server, every response is sanitised before it reaches the browser, and each section fails open independently so a down/misconfigured Tautulli never breaks the dashboard or page. Chart.js is self-hosted (`public/static/chart/`) for CSP compliance and reused by the existing Radarr stats chart.
 - **In-place quick-look on the dashboard.** Clicking any media tile — hero spotlight, upcoming, weekly trending, watchlist or latest additions — now opens a read-only detail modal right on the dashboard (poster, year, status, rating, genres, synopsis) instead of navigating away, with a deep-link to manage the item in Radarr/Sonarr or open it in Discover. Library items resolve from the already-cached dashboard aggregate (zero extra upstream calls on a warm page, falling back to a direct fetch on a miss); TMDb items resolve straight from TMDb. The fragment is read-only and fails open to a small graceful body, and the modal is Turbo-safe (declarative trigger, escaped values).
 - **Plex Activity page — statistics, graphs & a per-user filter.** The activity page's statistics gain Most Popular Movies / Shows tiles (ranked by distinct viewers), a Most Concurrent Streams tile, and a **Play Count ⇄ Play Duration** toggle that reformats every count-based tile and chart into watch time. Four new graphs are added — plays by source resolution, plays by stream resolution, streams by user, and concurrent streams over time (always a count, never reformatted as duration) — alongside a new privacy-safe **Users** overview table (friendly name, relative last-seen, last played, play count, total watch time). A page-wide **per-user filter** dropdown scopes the statistics, all graphs and the history grid to a single user, or all users (the Users overview table always lists everyone). The metric and user-id are clamped/validated server-side (`metric` ∈ `plays|duration`, user filter digits-only), every new client method and endpoint fails open to its neutral shape, and the allow-list keeps email / IP / avatar / Plex login off the wire — the opaque Tautulli user-id is a filter token only and never rendered. All data comes from read-only Tautulli commands (`get_home_stats`, `get_users_table`, `get_user_names`, `get_plays_by_*`, `get_concurrent_streams_by_stream_type`); strings are i18n'd (en/fr).

symfony/public/img/services/ATTRIBUTION.md

@@ -1,8 +1,8 @@
 # Service logos
 
 The service logo SVGs in this directory (radarr, sonarr, prowlarr,
-jellyseerr, qbittorrent, sabnzbd, nzbget, gluetun, tmdb) come from the
-**Dashboard Icons** collection:
+jellyseerr, qbittorrent, transmission, sabnzbd, nzbget, gluetun, tmdb) come
+from the **Dashboard Icons** collection:
 
 - Source: https://github.com/homarr-labs/dashboard-icons
 - License: Apache License 2.0

symfony/src/Controller/AdminSettingsController.php

@@ -69,6 +69,11 @@ class AdminSettingsController extends AbstractController
             ['key' => 'qbittorrent_user',     'type' => 'text',     'label' => 'admin.field.username',  'clearable' => true],
             ['key' => 'qbittorrent_password', 'type' => 'password', 'label' => 'admin.field.password',  'clearable' => true],
         ],
+        'transmission' => [
+            ['key' => 'transmission_url',      'type' => 'text',     'label' => 'admin.field.url',             'placeholder' => 'http://host.docker.internal:9091'],
+            ['key' => 'transmission_user',     'type' => 'text',     'label' => 'admin.field.username',  'clearable' => true],
+            ['key' => 'transmission_password', 'type' => 'password', 'label' => 'admin.field.password',  'clearable' => true],
+        ],
         'sabnzbd' => [
             ['key' => 'sabnzbd_url',     'type' => 'text',     'label' => 'admin.field.url',     'placeholder' => 'http://host.docker.internal:8080'],
             ['key' => 'sabnzbd_api_key', 'type' => 'password', 'label' => 'admin.field.api_key'],
@@ -128,6 +133,7 @@ class AdminSettingsController extends AbstractController
         'prowlarr'    => 'Prowlarr',
         'jellyseerr'  => 'Seerr',
         'qbittorrent' => 'qBittorrent',
+        'transmission' => 'Transmission',
         'sabnzbd'     => 'SABnzbd',
         'nzbget'      => 'NZBGet',
         'gluetun'     => 'Gluetun',
@@ -231,6 +237,19 @@ class AdminSettingsController extends AbstractController
             ],
             'help' => 'admin.display.qbit_refresh.help',
         ],
+        'display_transmission_refresh' => [
+            'label'   => 'admin.display.transmission_refresh.label',
+            'type'    => 'select',
+            'default' => '2',
+            'options' => [
+                '1'  => 'admin.display.transmission_refresh.options.1',
+                '2'  => 'admin.display.transmission_refresh.options.2',
+                '5'  => 'admin.display.transmission_refresh.options.5',
+                '10' => 'admin.display.transmission_refresh.options.10',
+                '0'  => 'admin.display.transmission_refresh.options.0',
+            ],
+            'help' => 'admin.display.transmission_refresh.help',
+        ],
         'display_ui_density' => [
             'label'   => 'admin.display.ui_density.label',
             'type'    => 'select',
@@ -476,6 +495,7 @@ public function test(string $service, Request $request): JsonResponse
             'radarr', 'sonarr', 'prowlarr', 'jellyseerr' => [$service . '_url', $service . '_api_key'],
             'tmdb'                                       => ['tmdb_api_key'],
             'qbittorrent'                                => ['qbittorrent_url', 'qbittorrent_user', 'qbittorrent_password'],
+            'transmission'                               => ['transmission_url', 'transmission_user', 'transmission_password'],
             'sabnzbd'                                    => ['sabnzbd_url', 'sabnzbd_api_key'],
             'nzbget'                                     => ['nzbget_url', 'nzbget_user', 'nzbget_password'],
             'tautulli'                                   => ['tautulli_url', 'tautulli_api_key'],
@@ -527,7 +547,7 @@ public function test(string $service, Request $request): JsonResponse
     public function healthInvalidate(string $service): JsonResponse
     {
         $service = strtolower($service);
-        $allowed = ['radarr', 'sonarr', 'prowlarr', 'jellyseerr', 'qbittorrent', 'tmdb', 'sabnzbd', 'nzbget', 'tautulli'];
+        $allowed = ['radarr', 'sonarr', 'prowlarr', 'jellyseerr', 'qbittorrent', 'transmission', 'tmdb', 'sabnzbd', 'nzbget', 'tautulli'];
         if (!in_array($service, $allowed, true)) {
             return new JsonResponse(['ok' => false], 400);
         }

symfony/src/Controller/Concerns/ApiClientErrorTrait.php

@@ -7,6 +7,7 @@
 use App\Service\Media\QBittorrentClient;
 use App\Service\Media\RadarrClient;
 use App\Service\Media\SonarrClient;
+use App\Service\Media\TransmissionClient;
 use Symfony\Component\HttpFoundation\JsonResponse;
 
 /**
@@ -34,7 +35,7 @@ trait ApiClientErrorTrait
      * Returns a generic fallback if the client did not record a structured error
      * (e.g. exception thrown before any HTTP call).
      */
-    private function buildClientErrorFlash(string $service, RadarrClient|SonarrClient|ProwlarrClient|JellyseerrClient|QBittorrentClient $client, ?string $fallback = null): string
+    private function buildClientErrorFlash(string $service, RadarrClient|SonarrClient|ProwlarrClient|JellyseerrClient|QBittorrentClient|TransmissionClient $client, ?string $fallback = null): string
     {
         $err = $client->getLastError();
         if ($err === null) {
@@ -58,7 +59,7 @@ private function buildClientErrorFlash(string $service, RadarrClient|SonarrClien
      * Output shape:
      *   { ok: false, error: string, http_code: int, service: string, path: string, method: string }
      */
-    private function jsonClientError(string $service, RadarrClient|SonarrClient|ProwlarrClient|JellyseerrClient|QBittorrentClient $client, ?string $fallback = null, int $statusCode = 500): JsonResponse
+    private function jsonClientError(string $service, RadarrClient|SonarrClient|ProwlarrClient|JellyseerrClient|QBittorrentClient|TransmissionClient $client, ?string $fallback = null, int $statusCode = 500): JsonResponse
     {
         $err = $client->getLastError();
         if ($err === null) {

symfony/src/Controller/HealthController.php

@@ -13,7 +13,7 @@
 class HealthController extends AbstractController
 {
     /** Single-instance services — kept on the legacy flat ping API. */
-    private const FLAT_SERVICES = ['prowlarr', 'jellyseerr', 'qbittorrent', 'sabnzbd', 'nzbget', 'tmdb'];
+    private const FLAT_SERVICES = ['prowlarr', 'jellyseerr', 'qbittorrent', 'transmission', 'sabnzbd', 'nzbget', 'tmdb'];
 
     #[Route('/api/health', name: 'api_health', methods: ['GET'])]
     public function health(Connection $db): JsonResponse