feat: add Atlassian OAuth support for Jira and Confluence

- Introduced a shared schema for Atlassian OAuth 2.0 credentials, accommodating both Jira and Confluence.
- Updated Jira connector routes to utilize the new AtlassianAuthCredentialsBase for handling OAuth tokens.
- Enhanced configuration to include new environment variables for Jira OAuth integration.
- Refactored token handling in Jira indexing logic to support the new shared credential structure.

surfsense_backend/app/schemas/atlassian_auth_credentials.py

@@ -0,0 +1,87 @@
+"""
+Atlassian OAuth 2.0 Authentication Credentials Schema.
+
+Shared schema for both Jira and Confluence OAuth credentials.
+Both products use the same Atlassian OAuth 2.0 (3LO) flow and token structure.
+"""
+
+from datetime import UTC, datetime
+
+from pydantic import BaseModel, field_validator
+
+
+class AtlassianAuthCredentialsBase(BaseModel):
+    """
+    Base model for Atlassian OAuth 2.0 credentials.
+    
+    Used for both Jira and Confluence connectors since they share
+    the same Atlassian OAuth infrastructure and token structure.
+    """
+
+    access_token: str
+    refresh_token: str | None = None
+    token_type: str = "Bearer"
+    expires_in: int | None = None
+    expires_at: datetime | None = None
+    scope: str | None = None
+    cloud_id: str | None = None
+    base_url: str | None = None
+
+    @property
+    def is_expired(self) -> bool:
+        """Check if the credentials have expired."""
+        if self.expires_at is None:
+            return False
+        return self.expires_at <= datetime.now(UTC)
+
+    @property
+    def is_refreshable(self) -> bool:
+        """Check if the credentials can be refreshed."""
+        return self.refresh_token is not None
+
+    def to_dict(self) -> dict:
+        """Convert credentials to dictionary for storage."""
+        return {
+            "access_token": self.access_token,
+            "refresh_token": self.refresh_token,
+            "token_type": self.token_type,
+            "expires_in": self.expires_in,
+            "expires_at": self.expires_at.isoformat() if self.expires_at else None,
+            "scope": self.scope,
+            "cloud_id": self.cloud_id,
+            "base_url": self.base_url,
+        }
+
+    @classmethod
+    def from_dict(cls, data: dict) -> "AtlassianAuthCredentialsBase":
+        """Create credentials from dictionary."""
+        expires_at = None
+        if data.get("expires_at"):
+            expires_at = datetime.fromisoformat(data["expires_at"])
+
+        return cls(
+            access_token=data["access_token"],
+            refresh_token=data.get("refresh_token"),
+            token_type=data.get("token_type", "Bearer"),
+            expires_in=data.get("expires_in"),
+            expires_at=expires_at,
+            scope=data.get("scope"),
+            cloud_id=data.get("cloud_id"),
+            base_url=data.get("base_url"),
+        )
+
+    @field_validator("expires_at", mode="before")
+    @classmethod
+    def ensure_aware_utc(cls, v):
+        # Strings like "2025-08-26T14:46:57.367184"
+        if isinstance(v, str):
+            # add +00:00 if missing tz info
+            if v.endswith("Z"):
+                return datetime.fromisoformat(v.replace("Z", "+00:00"))
+            dt = datetime.fromisoformat(v)
+            return dt if dt.tzinfo else dt.replace(tzinfo=UTC)
+        # datetime objects
+        if isinstance(v, datetime):
+            return v if v.tzinfo else v.replace(tzinfo=UTC)
+        return v
+