feat: sync recent call and channel fixes

deploy/migrations/0040_discard_empty_conferences.up.sql

@@ -0,0 +1,31 @@
+WITH stale AS (
+    SELECT c.call_id
+    FROM public.group_calls c
+    WHERE c.kind = 'conference'::text
+      AND c.state = 'active'::text
+      AND EXISTS (
+          SELECT 1
+          FROM public.group_call_participants p
+          WHERE p.call_id = c.call_id
+      )
+      AND NOT EXISTS (
+          SELECT 1
+          FROM public.group_call_participants p
+          WHERE p.call_id = c.call_id
+            AND NOT p.left_call
+      )
+)
+UPDATE public.group_calls c
+SET state = 'discarded'::text,
+    discarded_at = CASE
+        WHEN c.discarded_at = 0 THEN EXTRACT(EPOCH FROM now())::integer
+        ELSE c.discarded_at
+    END,
+    duration = CASE
+        WHEN c.duration = 0 THEN GREATEST(0, EXTRACT(EPOCH FROM now())::integer - c.created_at)
+        ELSE c.duration
+    END,
+    participants_count = 0,
+    version = c.version + 1
+FROM stale
+WHERE c.call_id = stale.call_id;