Fix: Resolved HF runtime errors (casing, permissions, and module imports).

Dockerfile

@@ -19,6 +19,10 @@ RUN apt-get update && apt-get install -y --no-install-recommends gcc python3-dev
 
 USER user
 ENV PATH="/home/user/.local/bin:$PATH"
+USER root
+RUN mkdir -p /data/db && chown -R user:user /data
+USER user
+
 WORKDIR /home/user/app
 
 # Install PyTorch CPU-only FIRST (largest package, separate cache layer)

backend/database.py

@@ -3,15 +3,31 @@ import os
 from datetime import datetime
 
 # HF Native Persistence: Check if /data volume is mounted
-IF_HF_PERSISTENT = os.path.exists('/data')
-if IF_HF_PERSISTENT:
-    DB_FILE = '/data/db.json'
-    print(f"📡 HF Native Persistence: Active. Storing data in {DB_FILE}")
-else:
-    DB_FILE = os.path.join(os.path.dirname(__file__), 'data', 'db.json')
-    print(f"💻 Local Persistence: Active. Storing data in {DB_FILE}")
-
-# Ensure data directory exists
+def get_db_file_path():
+    # Primary choice: HF Persistent Storage Mount
+    if os.path.exists('/data'):
+        # Use a subdirectory to avoid permission issues at the root mount point
+        test_path = '/data/db/db.json'
+        try:
+            os.makedirs(os.path.dirname(test_path), exist_ok=True)
+            # Verify write access
+            with open(os.path.join(os.path.dirname(test_path), '.write_test'), 'w') as f:
+                f.write('test')
+            os.remove(os.path.join(os.path.dirname(test_path), '.write_test'))
+            print(f"📡 HF Native Persistence: Verified. Storing data in {test_path}")
+            return test_path
+        except Exception as e:
+            print(f"⚠️ HF Native Persistence: (/data) exists but is not writable: {e}")
+    
+    # Fallback: Local Storage
+    local_path = os.path.join(os.path.dirname(__file__), 'data', 'db.json')
+    os.makedirs(os.path.dirname(local_path), exist_ok=True)
+    print(f"💻 Local Persistence: Active. Storing data in {local_path}")
+    return local_path
+
+DB_FILE = get_db_file_path()
+
+# Ensure final data directory exists
 os.makedirs(os.path.dirname(DB_FILE), exist_ok=True)
 
 def init_db():

backend/navigator.py

@@ -23,7 +23,7 @@ import numpy as np
 # ──────────────────────────────────────────────
 # Model Definition — must match training architecture
 # ──────────────────────────────────────────────
-_MODEL_PATH = os.path.join(os.path.dirname(__file__), '..', 'Navigators', 'dqn_model.pth')
+_MODEL_PATH = os.path.join(os.path.dirname(__file__), '..', 'navigators', 'dqn_model.pth')
 
 _dqn_net = None
 _dqn_mode = "unavailable"

backend/nlp_api.py

@@ -255,7 +255,7 @@ def reset_database():
 def get_resources():
     """Get all NLP learning resources with their grid positions and correct visited state"""
     session_id = request.args.get('session_id', 'default')
-    from database import get_session
+    from .database import get_session
     session = get_session(session_id)
     visited_ids = set(str(v).strip() for v in session.get('visitedResources', []))
     
@@ -311,7 +311,7 @@ def move_agent():
 def get_notifications():
     """Get all notifications for a session"""
     session_id = request.args.get('session_id', 'default')
-    from database import get_session
+    from .database import get_session
     session = get_session(session_id)
     return jsonify(session.get('notifications', []))
 
@@ -327,7 +327,7 @@ def add_notification():
     if not message:
         return jsonify({'error': 'Message required'}), 400
         
-    from database import get_session, update_session
+    from .database import get_session, update_session
     session = get_session(session_id)
     if 'notifications' not in session:
         session['notifications'] = []
@@ -351,7 +351,7 @@ def mark_notifications_read():
     data = request.get_json()
     session_id = data.get('session_id', 'default')
     
-    from database import get_session, update_session
+    from .database import get_session, update_session
     session = get_session(session_id)
     if 'notifications' in session:
         for n in session['notifications']:
@@ -863,7 +863,7 @@ def get_learning_data():
     ai_analysis = ""
     xp_earned = 0
     try:
-        from database import load_db
+        from .database import load_db
         db = load_db()
         # Find latest summary for this session (they contain session_id in their ID or we match title)
         matching_summaries = [s for s in db.get('summaries', []) if f"summary_{session_id}" in s.get('id', '')]
@@ -883,7 +883,7 @@ def get_learning_data():
     activity_heatmap = {}
     activity_log = []
     try:
-        from database import load_db
+        from .database import load_db
         db = load_db()
         all_summaries = db.get('summaries', [])
         
@@ -961,7 +961,7 @@ def get_learning_data():
 def get_bookmarks():
     """Get all bookmarked resources for a session"""
     session_id = request.args.get('session_id', 'default')
-    from database import get_bookmarks as get_db_bookmarks
+    from .database import get_bookmarks as get_db_bookmarks
     return jsonify(get_db_bookmarks(session_id))
 
 
@@ -975,7 +975,7 @@ def add_bookmark():
     if not resource_id:
         return jsonify({'error': 'Resource ID required'}), 400
         
-    from database import add_bookmark as add_db_bookmark
+    from .database import add_bookmark as add_db_bookmark
     add_db_bookmark(session_id, resource_id)
     return jsonify({'status': 'success', 'resource_id': resource_id})
 
@@ -990,7 +990,7 @@ def remove_bookmark():
     if not resource_id:
         return jsonify({'error': 'Resource ID required'}), 400
         
-    from database import remove_bookmark as remove_db_bookmark
+    from .database import remove_bookmark as remove_db_bookmark
     remove_db_bookmark(session_id, resource_id)
     return jsonify({'status': 'success', 'resource_id': resource_id})