fix: use JWTAlgorithm enum instead of raw string for JWTConfig.algorithm

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: rapsealk

src/ai/backend/common/configs/jwt.py

@@ -11,7 +11,12 @@
 from pydantic import AliasChoices, Field
 
 from ai.backend.common.config import BaseConfigSchema
-from ai.backend.common.jwt.config import JWTConfig as CoreJWTConfig
+from ai.backend.common.jwt.config import (
+    JWTAlgorithm as CoreJWTAlgorithm,
+)
+from ai.backend.common.jwt.config import (
+    JWTConfig as CoreJWTConfig,
+)
 from ai.backend.common.meta import BackendAIConfigMeta, ConfigExample
 
 
@@ -58,6 +63,6 @@ class SharedJWTConfig(BaseConfigSchema):
     def to_jwt_config(self) -> CoreJWTConfig:
         """Convert to ai.backend.common.jwt.config.JWTConfig."""
         return CoreJWTConfig(
-            algorithm=self.algorithm,
+            algorithm=CoreJWTAlgorithm(self.algorithm),
             token_expiration_seconds=self.token_expiration_seconds,
         )

tests/unit/common/jwt/test_signer.py

@@ -8,7 +8,7 @@
 import jwt as pyjwt
 import pytest
 
-from ai.backend.common.jwt.config import JWTConfig
+from ai.backend.common.jwt.config import JWTAlgorithm, JWTConfig
 from ai.backend.common.jwt.signer import JWTSigner
 from ai.backend.common.jwt.types import JWTUserContext
 from ai.backend.common.types import AccessKey
@@ -18,7 +18,7 @@
 def jwt_config() -> JWTConfig:
     """Create test JWT configuration."""
     return JWTConfig(
-        algorithm="HS256",
+        algorithm=JWTAlgorithm.HS256,
         token_expiration_seconds=900,
     )
 

tests/unit/common/jwt/test_validator.py

@@ -7,7 +7,7 @@
 import jwt as pyjwt
 import pytest
 
-from ai.backend.common.jwt.config import JWTConfig
+from ai.backend.common.jwt.config import JWTAlgorithm, JWTConfig
 from ai.backend.common.jwt.exceptions import (
     JWTDecodeError,
     JWTExpiredError,
@@ -24,7 +24,7 @@
 def jwt_config() -> JWTConfig:
     """Create test JWT configuration."""
     return JWTConfig(
-        algorithm="HS256",
+        algorithm=JWTAlgorithm.HS256,
         token_expiration_seconds=900,
     )