Feat: Support multiple data sources synchronizations (#10954)

### What problem does this PR solve?
#10953

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

common/data_source/teams_connector.py

@@ -0,0 +1,115 @@
+"""Microsoft Teams connector"""
+
+from typing import Any
+
+import msal
+from office365.graph_client import GraphClient
+from office365.runtime.client_request_exception import ClientRequestException
+
+from common.data_source.exceptions import (
+    ConnectorValidationError,
+    InsufficientPermissionsError,
+    UnexpectedValidationError, ConnectorMissingCredentialError
+)
+from common.data_source.interfaces import (
+    SecondsSinceUnixEpoch,
+    SlimConnectorWithPermSync, CheckpointedConnectorWithPermSync
+)
+from common.data_source.models import (
+    ConnectorCheckpoint
+)
+
+_SLIM_DOC_BATCH_SIZE = 5000
+
+
+class TeamsCheckpoint(ConnectorCheckpoint):
+    """Teams-specific checkpoint"""
+    todo_team_ids: list[str] | None = None
+
+
+class TeamsConnector(CheckpointedConnectorWithPermSync, SlimConnectorWithPermSync):
+    """Microsoft Teams connector for accessing Teams messages and channels"""
+
+    def __init__(self, batch_size: int = _SLIM_DOC_BATCH_SIZE) -> None:
+        self.batch_size = batch_size
+        self.teams_client = None
+
+    def load_credentials(self, credentials: dict[str, Any]) -> dict[str, Any] | None:
+        """Load Microsoft Teams credentials"""
+        try:
+            tenant_id = credentials.get("tenant_id")
+            client_id = credentials.get("client_id")
+            client_secret = credentials.get("client_secret")
+            
+            if not all([tenant_id, client_id, client_secret]):
+                raise ConnectorMissingCredentialError("Microsoft Teams credentials are incomplete")
+            
+            # Create MSAL confidential client
+            app = msal.ConfidentialClientApplication(
+                client_id=client_id,
+                client_credential=client_secret,
+                authority=f"https://login.microsoftonline.com/{tenant_id}"
+            )
+            
+            # Get access token
+            result = app.acquire_token_for_client(scopes=["https://graph.microsoft.com/.default"])
+            
+            if "access_token" not in result:
+                raise ConnectorMissingCredentialError("Failed to acquire Microsoft Teams access token")
+            
+            # Create Graph client for Teams
+            self.teams_client = GraphClient(result["access_token"])
+            
+            return None
+        except Exception as e:
+            raise ConnectorMissingCredentialError(f"Microsoft Teams: {e}")
+
+    def validate_connector_settings(self) -> None:
+        """Validate Microsoft Teams connector settings"""
+        if not self.teams_client:
+            raise ConnectorMissingCredentialError("Microsoft Teams")
+        
+        try:
+            # Test connection by getting teams
+            teams = self.teams_client.teams.get().execute_query()
+            if not teams:
+                raise ConnectorValidationError("Failed to access Microsoft Teams")
+        except ClientRequestException as e:
+            if "401" in str(e) or "403" in str(e):
+                raise InsufficientPermissionsError("Invalid credentials or insufficient permissions")
+            else:
+                raise UnexpectedValidationError(f"Microsoft Teams validation error: {e}")
+
+    def poll_source(self, start: SecondsSinceUnixEpoch, end: SecondsSinceUnixEpoch) -> Any:
+        """Poll Microsoft Teams for recent messages"""
+        # Simplified implementation - in production this would handle actual polling
+        return []
+
+    def load_from_checkpoint(
+        self,
+        start: SecondsSinceUnixEpoch,
+        end: SecondsSinceUnixEpoch,
+        checkpoint: ConnectorCheckpoint,
+    ) -> Any:
+        """Load documents from checkpoint"""
+        # Simplified implementation
+        return []
+
+    def build_dummy_checkpoint(self) -> ConnectorCheckpoint:
+        """Build dummy checkpoint"""
+        return TeamsCheckpoint()
+
+    def validate_checkpoint_json(self, checkpoint_json: str) -> ConnectorCheckpoint:
+        """Validate checkpoint JSON"""
+        # Simplified implementation
+        return TeamsCheckpoint()
+
+    def retrieve_all_slim_docs_perm_sync(
+        self,
+        start: SecondsSinceUnixEpoch | None = None,
+        end: SecondsSinceUnixEpoch | None = None,
+        callback: Any = None,
+    ) -> Any:
+        """Retrieve all simplified documents with permission sync"""
+        # Simplified implementation
+        return []