feat: Add combined track functionality with repository and service layers

- Introduced CombinedTrackModel, CombinedTrackCreate, and CombinedTrackRepository for managing combined tracks.
- Implemented logic to create combined tracks based on existing tracks between two stations.
- Added methods to check for existing combined tracks and retrieve constituent track IDs.
- Enhanced TrackModel and TrackRepository to support OSM ID and track updates.
- Created migration scripts for adding combined tracks table and OSM ID to tracks.
- Updated services and API endpoints to handle combined track operations.
- Added tests for combined track creation, repository methods, and API interactions.

scripts/init_demo_db.py

@@ -62,13 +62,23 @@ def check_database_url():
     print(f"Using database: {database_url}")
 
 
-def run_command(cmd, cwd=None, description=""):
+def run_command(cmd, cwd=None, description="", env=None):
     """Run a shell command and return the result."""
     print(f"\n>>> {description}")
     print(f"Running: {' '.join(cmd)}")
     try:
-        result = subprocess.run(cmd, cwd=cwd, check=True,
-                                capture_output=True, text=True)
+        env_vars = os.environ.copy()
+        if env:
+            env_vars.update(env)
+        env_vars.setdefault("PYTHONPATH", "/app")
+        result = subprocess.run(
+            cmd,
+            cwd=cwd,
+            check=True,
+            capture_output=True,
+            text=True,
+            env=env_vars,
+        )
         if result.stdout:
             print(result.stdout)
         return result
@@ -86,7 +96,7 @@ def run_migrations():
     run_command(
         ['alembic', 'upgrade', 'head'],
         cwd='backend',
-        description="Running database migrations"
+        description="Running database migrations",
     )