transmission, extracted into plugins/transmission — the platform half

Sixth extraction, straight after photos. Everything transmission now lives at
gitea.officer.dev/plugins/transmission.

Deleted, not commented: the sidecar, the api router, the Transmission app (28
files including detail/ and dialogs/), the screen, the App.tsx route pair, the
Dashboard barrel line, the usePageTitle rule, the AppRegistry wiring, the
officerdev barrel re-exports, the permission registry entry, the hono.ts import
and mount comments, and the app-store catalogue entry.

No database change: transmission owns no tables. Its connection lives in
service_connections, a core table it now depends on from outside — a real
coupling, recorded in the plugin's own PLUGIN.md rather than left to be
discovered.

── Test fixtures, repointed rather than deleted ──

Transmission was the canonical `members: 'none'` fixture — a single-tenant
daemon with no user concept — across three app-store test files. slskd has the
identical shape, so the assertions moved there. Deleting them would have
quietly dropped coverage of the no-members install path along with the plugin,
which is the same trap the vault extraction hit with `members: 'invite'`.

── Vocabulary swept, per the runbook ──

Six screens and two App.tsx comments pointed at `/photos` or `/transmission` as
the worked example of the Workspace/Panel shape. Both are plugins now, so those
pointers dangled at code no longer in the tree. Repointed at /command-hq and
/soulseek, which are core.

bunx tsgo clean. 1080 pass / 0 fail.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/apps/officer-web/App.tsx

@@ -50,7 +50,7 @@ export function App() {
         <Dashboard.DashboardLayout>
           <Routes>
             <Route path="/" element={<Dashboard.HomeScreen />} />
-            {/* Route pairs, like /offscale (a plugin now) and /photos below: the bare page route exists so the
+            {/* Route pairs, like /command-hq and /soulseek below: the bare page route exists so the
                 existing links into it keep working, and its `SettingsRoute` guard redirects to the
                 first section. The section is the URL rather than a `*_SELECTED` global, so a settings
                 sub-page is linkable, bookmarkable and cmd-clickable. */}
@@ -95,7 +95,7 @@ export function App() {
                 hands the whole subtree to the plugin's own router, which react-router nests natively. */}
             {installedPlugins.flatMap((plugin) => [
               <Route key={plugin.appName} path={plugin.route} element={<Dashboard.PluginScreen {...plugin} />} />,
-              // The section pair, exactly as the core screens do it (`/photos/:section`): the plugin's
+              // The section pair, exactly as the core screens do it (`/soulseek/:section`): the plugin's
               // panels read `useParams` themselves, so which section is open is the URL rather than state
               // passed between them.
               <Route
@@ -106,8 +106,6 @@ export function App() {
             ])}
             <Route path="/jellyfin" element={<Dashboard.JellyfinScreen />} />
             <Route path="/jellyfin/:section" element={<Dashboard.JellyfinScreen />} />
-            <Route path="/transmission" element={<Dashboard.TransmissionScreen />} />
-            <Route path="/transmission/:section" element={<Dashboard.TransmissionScreen />} />
             <Route path="/gitea" element={<Dashboard.GiteaScreen />} />
             <Route path="/gitea/:section" element={<Dashboard.GiteaScreen />} />
             <Route path="/gitea/repo/:owner/:name" element={<Dashboard.GiteaScreen />} />