Sessions leave redacted logs; viewers wait for a member relay's source before opening it

Logs: one redaction pass (query strings to names, member tokens,
passwords, cookies, auth headers) for every line; daily files with size
and age caps in the app (hosted server included) and the dedicated
server (--log-dir); swaps, relay channels, per-member /r /m /j outcomes,
server fetches, mpv load errors, yt-dlp runs. Settings > About: Copy
diagnostics, Open logs folder.

Bilibili through someone else: the viewer opened /r/ before the source
dialled in; the server holds that request and mpv gives up after 5 s
("could not be opened"). Viewers now open a member relay once it is
live, the putter starts its source before its own player, and track
sizes are read in parallel.

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

apps/desktop/lib/src/state/session_state.dart

@@ -379,7 +379,8 @@ class SessionState {
             ytDlpDir: await _sharedYtDlpDir(),
           ),
           loopbackOnly: soloSession,
-          onLog: (line) => debugPrint('[server] $line'),
+          // Its records join the app's log as `server.<logger>`.
+          onLog: (line) => relogLine('server', line),
           onCrash: (cause) => _onServerCrash(server, cause),
         );
       } catch (e, st) {