fix: cache Neo4j driver failure state to avoid 60s retry on every request

get_global_driver() now sets _driver_unavailable=True when the initial
connection fails, so subsequent calls fail immediately instead of
spending 60s retrying each time. Added reset_global_driver() to allow
manual reconnection after Neo4j comes back up.

Also fixes APP_BOLT_URL in .env: was bolt://bolt.classroomcopilot.ai
(public IP, port not exposed), now bolt://192.168.0.209:7687 (LAN).

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

modules/database/tools/neo4j_driver_tools.py

@@ -18,7 +18,7 @@ def _retry_with_backoff(
 ) -> any:
     """
     Helper function to retry operations with exponential backoff.
-    
+
     Args:
         func: Function to retry
         max_attempts: Maximum number of retry attempts
@@ -29,26 +29,26 @@ def _retry_with_backoff(
     attempt = 0
     delay = initial_delay
     start_time = time.time()
-    
+
     while attempt < max_attempts:
         try:
             return func()
         except Exception as e:
             attempt += 1
             elapsed_time = time.time() - start_time
-            
+
             # Check if we've exceeded the maximum total wait time
             if elapsed_time >= max_total_wait:
                 logger.error(f"Exceeded maximum total wait time of {max_total_wait} seconds")
                 raise
-            
+
             if attempt == max_attempts:
                 logger.error(f"Final attempt {attempt} failed: {e}")
                 raise
-            
+
             # Calculate next delay with exponential backoff, but cap it
             delay = min(delay * 2, max_delay)
-            
+
             # If we're in a container initialization scenario, provide more context
             if "Connection refused" in str(e):
                 logger.warning(
@@ -59,7 +59,7 @@ def _retry_with_backoff(
                 )
             else:
                 logger.warning(f"Attempt {attempt} failed: {e}. Retrying in {delay:.1f} seconds...")
-            
+
             time.sleep(delay)
 
 def get_driver(db_name: Optional[str] = None, url: Optional[str] = None, auth: Optional[Tuple[str, str]] = None) -> Optional[Driver]:
@@ -71,7 +71,7 @@ def get_driver(db_name: Optional[str] = None, url: Optional[str] = None, auth: O
             logger.error("Neo4j credentials not found in environment")
             return None
         auth = (username, password)
-    
+
     if auth is None:
         logger.error("No authentication credentials provided")
         return None
@@ -95,7 +95,7 @@ def get_driver(db_name: Optional[str] = None, url: Optional[str] = None, auth: O
     except Exception as e:
         logger.error(f"Failed to establish Neo4j connection after all retries: {e}")
         return None
-    
+
     # Test the connection with the specific database
     if db_name and driver:
         def verify_database():
@@ -127,27 +127,50 @@ def close_driver(driver: Optional[Driver]) -> None:
         logger.info("Closing driver")
         driver.close()
 
-# Global driver instance
+# Global driver instance — None means not yet initialised, _driver_unavailable=True means connection failed
 _driver: Optional[Driver] = None
+_driver_unavailable: bool = False
 
 def get_global_driver() -> Optional[Driver]:
-    """Get or create the global Neo4j driver instance."""
-    global _driver
+    """Get or create the global Neo4j driver instance.
+
+    Caches both success and failure so a broken Neo4j connection causes
+    a single 60-second retry at startup, then fast-fails on every
+    subsequent call instead of hanging for 60s each time.
+    """
+    global _driver, _driver_unavailable
+    if _driver_unavailable:
+        return None
     if _driver is None:
         _driver = get_driver()
+        if _driver is None:
+            _driver_unavailable = True
+            logger.error("Neo4j driver unavailable — all subsequent Neo4j calls will fail fast until process restarts")
     return _driver
 
+def reset_global_driver() -> None:
+    """Reset the cached driver, forcing a reconnection attempt on the next call.
+
+    Call this if Neo4j becomes available after the process started.
+    """
+    global _driver, _driver_unavailable
+    if _driver:
+        close_driver(_driver)
+    _driver = None
+    _driver_unavailable = False
+    logger.info("Global Neo4j driver reset — will reconnect on next request")
+
 @contextmanager
 def get_session(database: Optional[str] = None) -> Generator[Session, None, None]:
     """Get a Neo4j session using the global driver."""
     driver = get_global_driver()
     if driver is None:
         raise Exception("Failed to get Neo4j driver")
-    
+
     session = None
     try:
         session = driver.session(database=database)
         yield session
     finally:
         if session:
-            session.close()
+            session.close()