media_delivery: fix SUPER_REPL spam + streaming verification

Bugs fixed:
- md_super_peer_add: timeout_tb = 0 → MEDIA_REPL_TIMEOUT_TB (timer fired every poll)
- md_repl_retrans_cb: md from peer->connect_timer (garbage) → peer->md
- md_repl_retrans_cb: removed inflight_count=0 reset (don't resend acked entries)
- stream_ctx: removed unused block_data field (was NULL, caused crash in BLOCK_DONE)

Test improvements:
- stream_completed flag for reliable streaming verification
- File created in <db_dir>/media/ (matches media_index path logic)
- 9/9 full test, 33/33 total

src/media_delivery/media_delivery.c

@@ -173,6 +173,8 @@ static struct media_super_peer* md_super_peer_add(struct media_delivery_ctx* md,
     sp = (struct media_super_peer*)qe->data;
     memset(sp, 0, sizeof(*sp));
     sp->peer_node_id = node_id;
+    sp->timeout_tb = MEDIA_REPL_TIMEOUT_TB;
+    sp->md = md;
     memcpy(qe->data, &node_id, 8);
     queue_data_put_with_index(md->super_peers, qe);
     return sp;
@@ -193,14 +195,13 @@ static void md_super_peer_remove(struct media_delivery_ctx* md, uint64_t node_id
 
 static void md_repl_retrans_cb(void* arg) {
     struct media_super_peer* peer = (struct media_super_peer*)arg;
-    struct media_delivery_ctx* md = (struct media_delivery_ctx*)peer->connect_timer;
+    struct media_delivery_ctx* md = peer->md;
     if (!md || !peer->connected) return;
     peer->timeout_timer = NULL;
     peer->timeout_tb = peer->timeout_tb < MEDIA_REPL_TIMEOUT_MAX_TB / 2
         ? peer->timeout_tb * 2 : peer->timeout_tb;
     if (peer->timeout_tb > MEDIA_REPL_TIMEOUT_MAX_TB)
         peer->timeout_tb = MEDIA_REPL_TIMEOUT_MAX_TB;
-    peer->inflight_count = 0;
     md_super_repl_send(md, peer);
 }
 
@@ -669,7 +670,7 @@ static void md_handle_block_req(struct media_delivery_ctx* md, uint64_t from_nod
 /* ── decrement stream counter (called when stream finished/cancelled internally) ── */
 
 void media_delivery_stream_done(struct UTUN_INSTANCE* inst) {
-    if (inst) { struct media_delivery_ctx* md = &inst->md; if (md->active_streams > 0) md->active_streams--; }
+    if (inst) { struct media_delivery_ctx* md = &inst->md; if (md->active_streams > 0) md->active_streams--; md->stream_completed = 1; }
 }
 
 static void md_super_connect(struct media_delivery_ctx* md, uint64_t peer_node_id) {

src/media_delivery/media_delivery.h

@@ -35,6 +35,7 @@ struct media_super_peer {
     uint8_t  hello_done;        // 1 = SUPER_HELLO обмен завершён, можно реплицировать
     void*    timeout_timer;     // таймер ретрансмита
     void*    connect_timer;     // таймер переподключения (1 час при ошибке)
+    struct media_delivery_ctx* md; // обратная ссылка
 };
 
 struct media_served_node {
@@ -49,6 +50,7 @@ struct media_delivery_ctx {
     int      initialized;
     uint8_t  is_supernode;         // из adm_tags в peers_*
     uint8_t  active_streams;       // текущее число исходящих стримов (admission)
+    uint8_t  stream_completed;     // 1 = хотя бы один стрим завершился (для тестов)
     sqlite3* db;                   // = inst->topo_sqlite_db (кешируем для удобства)
     struct ll_queue* served_nodes;  // media_served_node — только суперузел
     struct ll_queue* super_peers;   // media_super_peer — только суперузел