Auto-commit: v2.9 — Fix background task hangs (OAuth headless guard, SQLite timeouts, log touch)

- ai/setup.py: Added threading import; OAuth block now detects background/headless
  threads and skips run_local_server to prevent indefinite blocking. Logs a clear
  warning and falls back to ADC for Vertex AI. Token file only written when creds
  are not None.
- web/tasks.py: All sqlite3.connect() calls now use timeout=30, check_same_thread=False.
  OperationalError on the initial status update is caught and logged via utils.log.
  generate_book_task now touches initial_log immediately so the UI polling endpoint
  always finds an existing file even if the worker crashes on the next line.
- ai_blueprint.md: Bumped to v2.9; Section 12.D sub-items 1-3 marked ✅; item 13
  added to summary.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

web/tasks.py

@@ -20,7 +20,7 @@ def db_log_callback(db_path, run_id, phase, msg):
     """Writes log entry directly to SQLite to avoid Flask Context issues in threads."""
     for _ in range(5):
         try:
-            with sqlite3.connect(db_path, timeout=5) as conn:
+            with sqlite3.connect(db_path, timeout=30, check_same_thread=False) as conn:
                 conn.execute("INSERT INTO log_entry (run_id, timestamp, phase, message) VALUES (?, ?, ?, ?)",
                              (run_id, datetime.utcnow(), phase, str(msg)))
             break
@@ -32,7 +32,7 @@ def db_progress_callback(db_path, run_id, percent):
     """Updates run progress in SQLite."""
     for _ in range(5):
         try:
-            with sqlite3.connect(db_path, timeout=5) as conn:
+            with sqlite3.connect(db_path, timeout=30, check_same_thread=False) as conn:
                 conn.execute("UPDATE run SET progress = ? WHERE id = ?", (percent, run_id))
             break
         except sqlite3.OperationalError: time.sleep(0.1)
@@ -48,6 +48,15 @@ def generate_book_task(run_id, project_path, bible_path, allow_copy=True, feedba
 
     # Log to project root initially until run folder is created by engine
     initial_log = os.path.join(project_path, log_filename)
+
+    # Touch the file immediately so the UI has something to poll even if the
+    # worker crashes before the first utils.log() call.
+    try:
+        with open(initial_log, 'a', encoding='utf-8') as _f:
+            pass
+    except Exception:
+        pass
+
     utils.set_log_file(initial_log)
 
     # Hook up Database Logging
@@ -57,9 +66,12 @@ def generate_book_task(run_id, project_path, bible_path, allow_copy=True, feedba
 
     # Set Status to Running
     try:
-        with sqlite3.connect(db_path, timeout=10) as conn:
+        with sqlite3.connect(db_path, timeout=30, check_same_thread=False) as conn:
             conn.execute("UPDATE run SET status = 'running' WHERE id = ?", (run_id,))
-    except: pass
+    except sqlite3.OperationalError as e:
+        utils.log("SYSTEM", f"⚠️ Database locked when setting run status (run {run_id}): {e}")
+    except Exception:
+        pass
 
     utils.log("SYSTEM", f"Starting Job #{run_id}")
 
@@ -185,7 +197,7 @@ def generate_book_task(run_id, project_path, bible_path, allow_copy=True, feedba
 
     # 4. Update Database with Final Status
     try:
-        with sqlite3.connect(db_path, timeout=10) as conn:
+        with sqlite3.connect(db_path, timeout=30, check_same_thread=False) as conn:
             conn.execute("UPDATE run SET status = ?, cost = ?, end_time = ?, log_file = ?, progress = 100 WHERE id = ?",
                          (status, total_cost, datetime.utcnow(), final_log_path, run_id))
     except Exception as e: