Apply retrieval settings to a source synced from the connect wizard

The connection setup endpoint takes sync.config, validated like an
upload's config, and passes it to the ingest task so the synced source
gets the chosen chunking and retrieval settings. An invalid config is
refused before the idempotency key is claimed.

docsgpt/api/connector/connections.py

@@ -230,8 +230,8 @@ class ConnectionSetup(Resource):
     @api.doc(
         description=(
             "Apply the connect wizard's choices: {create_tools, allow_writes?, tool_permissions?, "
-            "sync?: {items, frequency, name?}}. allow_writes points GitHub's tool at its write endpoint. "
-            "Honours an Idempotency-Key header for the sync."
+            "sync?: {items, frequency, name?, config?}}. allow_writes points GitHub's tool at its write "
+            "endpoint. config is the synced source's retrieval settings, validated like an upload's. Honours an Idempotency-Key header for the sync."
         )
     )
     def post(self, connection_id: str):
@@ -298,11 +298,19 @@ class ConnectionSetup(Resource):
 def _start_sync(user_id: str, row: dict, sync: dict):
     """Queue the first ingest of a source synced from ``row``.
 
-    Returns the source summary, or ``(message, status)`` on a bad request.
+    Args:
+        user_id: The connection's owner.
+        row: The connection row.
+        sync: ``{items, frequency, name?, config?}``. ``config`` is the source's
+            retrieval settings (a ``SourceConfig``), applied as an upload's are.
+
+    Returns:
+        The source summary, or ``(message, status)`` on a bad request.
     """
     from docsgpt.api.user.sources.upload import (
         _claim_task_or_get_cached,
         _derive_source_id,
+        _parse_source_config,
         _read_idempotency_key,
         _scoped_idempotency_key,
     )
@@ -318,6 +326,9 @@ def _start_sync(user_id: str, row: dict, sync: dict):
     if frequency not in _FREQUENCIES:
         return ("Unknown sync frequency", 400)
     name = (sync.get("name") or "").strip()
+    source_config, config_error = _parse_source_config(sync.get("config"))
+    if config_error is not None:
+        return ("Invalid source config", 400)
     if definition.sync_ingestor == "github":
         from docsgpt.parser.remote.github_loader import GitHubLoader
 
@@ -352,6 +363,7 @@ def _start_sync(user_id: str, row: dict, sync: dict):
             "folder_ids": folder_ids,
             "recursive": bool(items.get("recursive", True)),
             "sync_frequency": frequency,
+            "config": source_config,
         }
     else:
         if definition.sync_ingestor == "linear":
@@ -371,6 +383,7 @@ def _start_sync(user_id: str, row: dict, sync: dict):
             "loader": definition.sync_ingestor,
             "connection_id": str(row["id"]),
             "sync_frequency": frequency,
+            "config": source_config,
         }
     idempotency_key, _ = _read_idempotency_key()
     scoped_key = _scoped_idempotency_key(idempotency_key, user_id)