feat(auth): implement JWT TTL and expiration

added access_token_ttl setting
fixed public and private key mismatch while decoding jwt
decode_jwt now returns None on expired tokens instead of raising exc
generate_pair converts sub to string and uses dynamic expiration

schemas/jwt.py

@@ -1,11 +1,10 @@
-from datetime import UTC, datetime
-
 from pydantic import BaseModel, Field
 
+from core.exp import get_exp
 from schemas.providers import ProvidersType
 
 
 class JWTPayload(BaseModel):
-    sub: int = Field(description="User ID")
+    sub: str = Field(description="User ID")
     iss: ProvidersType = Field(description="Issuer")
-    exp: float = Field(default_factory=lambda: datetime.now(UTC).timestamp())
+    exp: float = Field(default_factory=get_exp)