Pick clubs from the top three divisions, and stop the rail from crashing

The club shortcut now offers every club of the first three German
divisions instead of two hard-coded ones. Up to three can be active at
once; benjamin and tobiasb still start with Hansa and the VfB switched on.

Also fixes a crash on the left jump out of the channel list: the jump
targeted a FocusRequester bound to the selected rail row, and a row that
is scrolled out of a LazyColumn is not composed, so requesting focus on it
threw. Jumps are now attempted and fall back to normal focus movement.

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

app/src/main/java/dev/castarr/tv/AppState.kt

@@ -54,14 +54,21 @@ class AppState(
     private fun loadEnabledTeams(): Set<String> {
         val stored = prefs.getStringSet("teams", null)
         if (stored != null) return stored.toSet()
-        return setOfNotNull(dev.castarr.tv.data.TeamFilters.defaultKeyFor(auth.username))
+        return dev.castarr.tv.data.TeamFilters.defaultKeysFor(auth.username).toSet()
     }
 
-    fun toggleTeam(key: String) {
+    /** Returns false when the cap of [TeamFilters.MAX_ACTIVE] is reached. */
+    fun toggleTeam(key: String): Boolean {
+        if (key !in enabledTeams &&
+            enabledTeams.size >= dev.castarr.tv.data.TeamFilters.MAX_ACTIVE
+        ) {
+            return false
+        }
         enabledTeams =
             if (key in enabledTeams) enabledTeams - key else enabledTeams + key
         prefs.edit().putStringSet("teams", enabledTeams).apply()
         if (activeTeam == key && key !in enabledTeams) activeTeam = null
+        return true
     }
     var audioTracks by mutableStateOf<List<PlayerController.AudioTrack>>(emptyList())
         private set