Refactor database initialization and remove Alembic migrations

- Removed legacy Alembic migration files and consolidated schema management into a new Pydantic-backed initializer (`scripts/init_db.py`).
- Updated `main.py` to ensure the new DB initializer runs on startup, maintaining idempotency.
- Adjusted session management in `config/database.py` to prevent DetachedInstanceError.
- Introduced new enums in `models/enums.py` for better organization and clarity.
- Refactored various models to utilize the new enums, improving code maintainability.
- Enhanced middleware to handle JSON validation more robustly, ensuring non-JSON requests do not trigger JSON errors.
- Added tests for middleware and enums to ensure expected behavior and consistency.
- Updated changelog to reflect significant changes and improvements.

scripts/docker-entrypoint.sh

@@ -1,9 +0,0 @@
-#!/usr/bin/env sh
-set -e
-
-PYTHONPATH="/app:${PYTHONPATH}"
-export PYTHONPATH
-
-python -m scripts.run_migrations
-
-exec "$@"

scripts/run_migrations.py

@@ -1,42 +0,0 @@
-"""Utility for applying Alembic migrations before application startup."""
-from __future__ import annotations
-
-import logging
-from pathlib import Path
-
-from alembic import command
-from alembic.config import Config
-from dotenv import load_dotenv
-
-logging.basicConfig(level=logging.INFO)
-logger = logging.getLogger(__name__)
-
-
-def _load_env() -> None:
-    """Ensure environment variables from .env are available."""
-    load_dotenv()
-
-
-def _alembic_config(project_root: Path) -> Config:
-    config_path = project_root / "alembic.ini"
-    if not config_path.exists():
-        raise FileNotFoundError(f"Missing alembic.ini at {config_path}")
-
-    config = Config(str(config_path))
-    config.set_main_option("script_location", str(project_root / "alembic"))
-    return config
-
-
-def run_migrations(target_revision: str = "head") -> None:
-    """Apply Alembic migrations up to the given revision."""
-    project_root = Path(__file__).resolve().parent.parent
-    _load_env()
-
-    config = _alembic_config(project_root)
-    logger.info("Applying database migrations up to %s", target_revision)
-    command.upgrade(config, target_revision)
-    logger.info("Database migrations applied successfully")
-
-
-if __name__ == "__main__":
-    run_migrations()