feat: production deployment - full update with providers, admin, glossaries, pricing, tests

Major changes across backend, frontend, infrastructure:
- Provider system with model selection (Google, DeepL, OpenAI, Ollama, Google Cloud)
- Admin panel: user management, pricing, settings
- Glossary system with CSV import/export
- Subscription and tier quota management
- Security hardening (rate limiting, API key auth, path traversal fixes)
- Docker compose for dev, prod, and IONOS deployment
- Alembic migrations for new tables
- Frontend: dashboard, pricing page, landing page, i18n (en/fr)
- Test suite and verification scripts

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

alembic/env.py

@@ -1,51 +1,46 @@
 """
-Alembic environment configuration
+Alembic environment configuration - Async support
 """
+
 import os
 import sys
+import asyncio
 from logging.config import fileConfig
 
-from sqlalchemy import engine_from_config
 from sqlalchemy import pool
+from sqlalchemy.engine import Connection
+from sqlalchemy.ext.asyncio import create_async_engine
 
 from alembic import context
 
-# Add parent directory to path for imports
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
-# this is the Alembic Config object
 config = context.config
 
-# Interpret the config file for Python logging
 if config.config_file_name is not None:
     fileConfig(config.config_file_name)
 
-# Import models for autogenerate support
 from database.models import Base
+from database.utils import convert_to_async_url
+
 target_metadata = Base.metadata
 
-# Get database URL from environment
 from dotenv import load_dotenv
+
 load_dotenv()
 
+# Use config so DATABASE_URL is built from POSTGRES_* when set (Story 6.6)
+import config as _app_config  # noqa: E402, F401
+
 DATABASE_URL = os.getenv("DATABASE_URL", "")
 if not DATABASE_URL:
     SQLITE_PATH = os.getenv("SQLITE_PATH", "data/translate.db")
     DATABASE_URL = f"sqlite:///./{SQLITE_PATH}"
 
-# Override sqlalchemy.url with environment variable
-config.set_main_option("sqlalchemy.url", DATABASE_URL)
-
 
 def run_migrations_offline() -> None:
-    """Run migrations in 'offline' mode.
-    
-    This configures the context with just a URL
-    and not an Engine, though an Engine is acceptable
-    here as well.  By skipping the Engine creation
-    we don't even need a DBAPI to be available.
-    """
-    url = config.get_main_option("sqlalchemy.url")
+    """Run migrations in 'offline' mode."""
+    url = config.get_main_option("sqlalchemy.url") or DATABASE_URL
     context.configure(
         url=url,
         target_metadata=target_metadata,
@@ -57,27 +52,33 @@ def run_migrations_offline() -> None:
         context.run_migrations()
 
 
-def run_migrations_online() -> None:
-    """Run migrations in 'online' mode.
-    
-    In this scenario we need to create an Engine
-    and associate a connection with the context.
-    """
-    connectable = engine_from_config(
-        config.get_section(config.config_ini_section, {}),
-        prefix="sqlalchemy.",
+def do_run_migrations(connection: Connection) -> None:
+    """Run migrations with the given connection"""
+    context.configure(
+        connection=connection, target_metadata=target_metadata, compare_type=True
+    )
+
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+async def run_async_migrations() -> None:
+    """Run migrations in async mode"""
+    async_url = convert_to_async_url(DATABASE_URL)
+    connectable = create_async_engine(
+        async_url,
         poolclass=pool.NullPool,
     )
 
-    with connectable.connect() as connection:
-        context.configure(
-            connection=connection, 
-            target_metadata=target_metadata,
-            compare_type=True,
-        )
+    async with connectable.connect() as connection:
+        await connection.run_sync(do_run_migrations)
 
-        with context.begin_transaction():
-            context.run_migrations()
+    await connectable.dispose()
+
+
+def run_migrations_online() -> None:
+    """Run migrations in 'online' mode with async support."""
+    asyncio.run(run_async_migrations())
 
 
 if context.is_offline_mode():