fix: test isolation + auth import compatibility + add optuna to requirements (HRT-136)

Test isolation fixes:
- auth_db.get_db(): read TURF_SAAS_DB dynamically (not frozen at import)
- api_v1/utils.get_db(): read TURF_SAAS_DB dynamically (not frozen at import)
- api_tokens_db.get_db(): read TURF_SAAS_DB dynamically (not frozen at import)
- tests/test_history.py: enforce _tmp_db.name + call init_auth_tables() in fixtures
- tests/test_user_tokens.py: enforce _tmp_db.name + call migrate_api_tokens_tables() in app fixture

Auth compatibility fixes:
- api_v1/routes/history.py: use auth.jwt_required_middleware (flask_jwt_extended)
  with saas_auth fallback for portal_server context
- api_v1/routes/ml_feedback.py: same auth import strategy
- api_v1/routes/user.py: same auth import strategy

Dependencies:
- requirements.txt: add optuna>=4.0.0 (used in ML ensemble tests and training)

Co-Authored-By: Paperclip <noreply@paperclip.ing>

api_v1/routes/history.py

@@ -20,7 +20,11 @@ from api_v1.utils import (
     get_pagination_params,
     paginate_query,
 )
-from saas_auth import require_auth as jwt_required_middleware
+# Auth: try flask_jwt_extended (app_v1) first, fall back to saas_auth (portal_server)
+try:
+    from auth import jwt_required_middleware
+except ImportError:
+    from saas_auth import require_auth as jwt_required_middleware
 
 history_bp = Blueprint("v1_history", __name__, url_prefix="/api/v1/history")
 

api_v1/routes/ml_feedback.py

@@ -20,7 +20,11 @@ from flask import Blueprint, jsonify, request, g
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.dirname(__file__))))
 
 from api_v1.utils import get_db, internal_error, bad_request
-from saas_auth import require_auth as jwt_required_middleware
+# Auth: try flask_jwt_extended (app_v1) first, fall back to saas_auth (portal_server)
+try:
+    from auth import jwt_required_middleware
+except ImportError:
+    from saas_auth import require_auth as jwt_required_middleware
 try:
     from auth import plan_required
 except ImportError:

api_v1/routes/user.py

@@ -13,7 +13,11 @@ import sqlite3
 from flask import Blueprint, jsonify, request
 
 from api_v1.utils import internal_error, bad_request
-from saas_auth import require_auth as jwt_required_middleware
+# Auth: try flask_jwt_extended (app_v1) first, fall back to saas_auth (portal_server)
+try:
+    from auth import jwt_required_middleware
+except ImportError:
+    from saas_auth import require_auth as jwt_required_middleware
 try:
     from auth import plan_required
 except ImportError: