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>

tests/test_logging.py

@@ -0,0 +1,40 @@
+import json
+import logging
+
+from core.logging import configure_logging, get_logger, bind_request_context, clear_request_context
+
+
+def test_structlog_json_includes_request_and_user_id(capsys):
+    # Configure JSON logging at INFO level
+    configure_logging(json_logs=True, log_level="INFO")
+    logger = get_logger("test_logger")
+
+    # Bind context and emit a log
+    bind_request_context(request_id="req-1234", user_id="user-42")
+    logger.info("test_event", extra_field="value")
+    clear_request_context()
+
+    captured = capsys.readouterr().out.strip()
+    assert captured, "No log output captured"
+
+    # One line of JSON
+    log_obj = json.loads(captured)
+    assert log_obj.get("event") == "test_event"
+    assert log_obj.get("request_id") == "req-1234"
+    assert log_obj.get("user_id") == "user-42"
+    assert log_obj.get("level") in {"info", "INFO"}
+
+
+def test_stdlib_logging_also_goes_through_structlog(capsys):
+    configure_logging(json_logs=True, log_level="INFO")
+
+    logger = logging.getLogger("stdlib_logger")
+    logger.info("hello from stdlib")
+
+    captured = capsys.readouterr().out.strip()
+    assert captured, "No log output captured for stdlib logger"
+
+    log_obj = json.loads(captured)
+    assert log_obj.get("event") == "hello from stdlib"
+    assert log_obj.get("level") in {"info", "INFO"}
+