fix(progress): run sync adapter.generate in a thread so SSE events stream during generation

server/dialog.py

@@ -5,6 +5,7 @@ Generator is in this same file but added in Task 12.
 """
 from __future__ import annotations
 
+import asyncio
 import re
 from dataclasses import dataclass
 
@@ -112,7 +113,8 @@ async def generate_dialog(
     for i, turn in enumerate(turns):
         # Re-apply the same seed before each turn so the run is reproducible.
         apply_seed(seed_used)
-        wav_bytes, sr, adapter_seed_used = adapter.generate(
+        wav_bytes, sr, adapter_seed_used = await asyncio.to_thread(
+            adapter.generate,
             turn.text, paths[turn.speaker], language, params_for_call,
         )
         arr, _ = _decode_wav_to_mono_float(wav_bytes)

server/main.py

@@ -1,6 +1,7 @@
 """FastAPI application factory."""
 from __future__ import annotations
 
+import asyncio
 import json
 import os
 import tempfile
@@ -172,8 +173,8 @@ def build_app() -> FastAPI:
         bus = get_bus()
         try:
             async with bus.session("single", total_turns=1) as sess:
-                wav_bytes, _sr, seed_used = gen_fn(
-                    text, ref_path, language, json.loads(params or "{}")
+                wav_bytes, _sr, seed_used = await asyncio.to_thread(
+                    gen_fn, text, ref_path, language, json.loads(params or "{}"),
                 )
                 sess.set_seed(seed_used)
         except Exception as exc: