fix(chat): resolve Auto-route failover event-loop freeze (#812)

Root cause: ensure_structured_column() executed a synchronous blocking
engine.connect().execute(SELECT information_schema.columns ...) inside the
async request path (_build_chat_history / _maybe_compress_history), freezing
the uvicorn event loop and hanging all endpoints (~200s, recovered only by
docker restart).

Fix:
- chat_context.py: remove per-request ensure_structured_column() calls; run
  once idempotently at app startup (main.py lifespan). Use CURRENT_DATABASE()
  for PostgreSQL compatibility.
- main.py: add startup-only ensure_structured_column() hook (try/except).
- llm_client.py: trust_env=False + bounded httpx.Timeout/wait_for so broken
  endpoints fail fast instead of hanging the event loop.
- chat_service.py: run media generation in a background daemon thread with its
  own event loop (_launch_media_task_bg) so SSE end does not cancel image/video
  tasks (#811); remove TEMP faulthandler diagnostic.

Safe-align: persist accumulated live container changes (admin/*, knowledge,
market, models, config, observability, mcp_client, platform_knowledge,
im_bot_platform, chat_media, capability_registry, requirements) and add
workflow_templates.

Verified: live failover test (model-006 -> conn-refused) returns in ~1.9s with
concurrent login 0.83s/200; event-loop responsiveness restored (sub-second).

backend/python/app/api/admin/achievement_admin.py

@@ -284,7 +284,7 @@ async def claim_achievement_reward(
         
         # Mark reward as claimed
         _execute_raw(db, 
-            "UPDATE user_achievements SET reward_claimed = 1, claimed_at = NOW() WHERE user_id = :uid AND achievement_id = :aid",
+            "UPDATE user_achievements SET reward_claimed = true, claimed_at = NOW() WHERE user_id = :uid AND achievement_id = :aid",
             {"uid": user_id, "aid": ach_id})
         
         return {"code": 0, "message": "奖励领取成功"}

backend/python/app/api/admin/analytics_admin.py

@@ -316,7 +316,7 @@ async def create_dashboard(
         config_json = json.loads('[{"type":"stat","title":"暂无数据","metric":"none","chart_type":"number"}]')
 
     if is_default:
-        db.execute(text("UPDATE analytics_dashboards SET is_default=0"))
+        db.execute(text("UPDATE analytics_dashboards SET is_default=false"))
 
     db.execute(text("""
         INSERT INTO analytics_dashboards (id, name, description, config, is_default, created_by)
@@ -332,7 +332,7 @@ async def create_dashboard(
 @router.delete("/dashboards/{dashboard_id}")
 async def delete_dashboard(dashboard_id: str, db: Session = Depends(get_db), user=Depends(get_current_user)):
     """删除仪表盘"""
-    db.execute(text("DELETE FROM analytics_dashboards WHERE id=:id AND is_default=0"), {"id": dashboard_id})
+    db.execute(text("DELETE FROM analytics_dashboards WHERE id=:id AND is_default=false"), {"id": dashboard_id})
     db.commit()
     return {"code": 200, "data": {"message": "仪表盘已删除"}}
 

backend/python/app/api/admin/billing_admin.py

@@ -445,7 +445,7 @@ async def billing_stats(db: Session = Depends(get_db), user=Depends(get_current_
         SELECT DATE(created_at) as d, COALESCE(SUM(amount), 0) as rev
         FROM billing_transactions
         WHERE transaction_type='recharge' AND status='completed'
-          AND created_at >= DATE_SUB(NOW(), INTERVAL 7 DAY)
+          AND created_at >= NOW() - INTERVAL '7 DAY'
         GROUP BY DATE(created_at) ORDER BY d
     """)).fetchall()
     daily_revenue = [{"date": str(r[0]), "revenue": float(r[1])} for r in revenue_7d]

backend/python/app/api/admin/code_exec_admin.py

@@ -103,7 +103,7 @@ async def get_execution_stats(db: Session = Depends(get_db), _=Depends(get_curre
     try:
         total = _execute_raw(db, "SELECT COUNT(*) as cnt FROM code_exec_tasks")[0]["cnt"]
         today = _execute_raw(db,
-            "SELECT COUNT(*) as cnt FROM code_exec_tasks WHERE DATE(created_at) = CURDATE()")[0]["cnt"]
+            "SELECT COUNT(*) as cnt FROM code_exec_tasks WHERE DATE(created_at) = CURRENT_DATE")[0]["cnt"]
         success_count = _execute_raw(db,
             "SELECT COUNT(*) as cnt FROM code_exec_tasks WHERE exit_code = 0 AND error IS NULL")[0]["cnt"]
         failed_count = _execute_raw(db,

backend/python/app/api/admin/distro_admin.py

@@ -703,7 +703,7 @@ echo "Installation complete!"
 {d.get('version', '1.0.0')}
 
 ## Installation
-Run `bash install.sh` to install.
+Run \"bash install.sh\" to install.
 
 ## License
 A valid license key is required. Contact your administrator for details.

backend/python/app/api/admin/im_bot_admin.py

@@ -169,7 +169,7 @@ async def get_im_bot_stats(user=Depends(get_current_user)):
         today_stats = _row_to_dict(rows[0]) if rows else {"msg_in": 0, "msg_out": 0, "users": 0, "errors": 0}
 
         # Total routing rules
-        routes_count = _execute_raw(db, text("SELECT COUNT(*) as cnt FROM im_bot_routes WHERE is_active=1"))[0]._mapping['cnt']
+        routes_count = _execute_raw(db, text("SELECT COUNT(*) as cnt FROM im_bot_routes WHERE is_active=true"))[0]._mapping['cnt']
 
         return {
             "success": True,
@@ -202,7 +202,7 @@ async def get_dashboard(user=Depends(get_current_user)):
                    SUM(messages_out) as msg_out,
                    SUM(unique_users) as users
             FROM im_bot_daily_stats
-            WHERE stat_date >= DATE_SUB(CURDATE(), INTERVAL 7 DAY)
+            WHERE stat_date >= CURRENT_DATE - INTERVAL '7 DAY'
             GROUP BY stat_date
             ORDER BY stat_date
         """))
@@ -217,7 +217,7 @@ async def get_dashboard(user=Depends(get_current_user)):
             LEFT JOIN (
                 SELECT channel_id, SUM(messages_in + messages_out) as msg_count
                 FROM im_bot_daily_stats
-                WHERE stat_date >= DATE_SUB(CURDATE(), INTERVAL 30 DAY)
+                WHERE stat_date >= CURRENT_DATE - INTERVAL '30 DAY'
                 GROUP BY channel_id
             ) s ON c.id = s.channel_id
             ORDER BY c.created_at DESC
@@ -357,7 +357,7 @@ async def get_channel_detail(channel_id: str, user=Depends(get_current_user)):
             SELECT stat_date, messages_in, messages_out, unique_users, error_count
             FROM im_bot_daily_stats
             WHERE channel_id = :cid
-            AND stat_date >= DATE_SUB(CURDATE(), INTERVAL 7 DAY)
+            AND stat_date >= CURRENT_DATE - INTERVAL '7 DAY'
             ORDER BY stat_date
         """), {"cid": channel_id})
         channel['stats_7d'] = _rows_to_dict(stats)
@@ -428,7 +428,7 @@ async def activate_channel(channel_id: str, user=Depends(get_current_user)):
     db = SessionLocal()
     try:
         _execute_raw(db, text(
-            "UPDATE channels SET is_active=1, status='connected' WHERE id=:cid"
+            "UPDATE channels SET is_active=true, status='connected' WHERE id=:cid"
         ), {"cid": channel_id})
         return {"success": True, "message": "Channel activated"}
     except Exception as e:
@@ -443,7 +443,7 @@ async def deactivate_channel(channel_id: str, user=Depends(get_current_user)):
     db = SessionLocal()
     try:
         _execute_raw(db, text(
-            "UPDATE channels SET is_active=0, status='disconnected' WHERE id=:cid"
+            "UPDATE channels SET is_active=false, status='disconnected' WHERE id=:cid"
         ), {"cid": channel_id})
         return {"success": True, "message": "Channel deactivated"}
     except Exception as e:

backend/python/app/api/admin/privacy_admin.py

@@ -442,7 +442,7 @@ def revoke_license(
         raise HTTPException(404, "License not found")
 
     _execute_raw(db, text(
-        "UPDATE offline_licenses SET status = 'revoked', revoked_reason = :reason, is_active = 0 WHERE id = :lid"
+        "UPDATE offline_licenses SET status = 'revoked', revoked_reason = :reason, is_active = false WHERE id = :lid"
     ), {"reason": reason, "lid": license_id})
 
     return {"code": 0, "message": "License revoked"}
@@ -623,7 +623,7 @@ def get_usage_stats(db: Session = Depends(get_db)):
         "SELECT COUNT(DISTINCT user_hash) FROM usage_reports"
     ))
     today_reports = _execute_raw(db, text(
-        "SELECT COUNT(*) FROM usage_reports WHERE DATE(created_at) = CURDATE()"
+        "SELECT COUNT(*) FROM usage_reports WHERE DATE(created_at) = CURRENT_DATE"
     ))
     by_type = _execute_raw(db, text(
         "SELECT report_type, COUNT(*) as cnt FROM usage_reports GROUP BY report_type"