channels: keep the logged-in user's row when it has no videos

The per-user rows are built from the local video listing, so a channel
that never uploaded is invisible to the row build — and an account that
owns only such channels lost its row entirely. tvbot is exactly that
case: the local tvbots channel exists, it has no videos, and while
logged in as tvbot the screen opened on the next user's channels.

The row build now merges the logged-in user's own local channels from
the account-channels listing (already fetched, carries the full card
data) into the locals before grouping; the group sort already puts the
own row first. Verified on the emulator logged in as tvbot: the
"tvbot's Channels" row renders first with the video-less tvbots card.

app/src/main/java/net/jeena/jtubetv/ui/screens/ChannelsScreen.kt

@@ -270,7 +270,19 @@ class ChannelsViewModel(private val store: TokenStore) : ViewModel() {
     }
 
     private fun rebuildRowsInner(host: String?) {
-        val locals = allChannels.filter { it.host == host }
+        val allLocals = allChannels.filter { it.host == host }
+        // The video-listing fast path cannot see channels with no videos at all —
+        // an account owning only such channels used to lose its row entirely
+        // (tvbot: the local tvbots channel exists, it just never uploaded). Merge
+        // the logged-in user's own local channels in; the group sort below still
+        // puts the own row first. The account-channels listing already carries
+        // the full card shape (avatar/banners/followers), no extra calls.
+        var locals = allLocals
+        if (userChannels.isNotEmpty()) {
+            val missing = userChannels
+                .filter { it.host == host && allLocals.none { l -> l.name == it.name } }
+            if (missing.isNotEmpty()) locals = allLocals + missing
+        }
         val ownNames = userChannels.map { c -> c.name }.toSet()
         val byOwner = locals.groupBy { ownerKey(it) }
         val groups = byOwner.values.map { row ->