fix(webhook): fetch description from Plane API on status-start

Plane issue.updated (status -> In Progress) ships only changed fields, so the
webhook payload has no description and QG-0 wrongly blocked issues. start_pipeline
now pulls the full description from the Plane issue detail API (reusing the same
GET endpoint + shared token as fetch_issue_sequence_id) when the payload field is
empty/short, before QG-0 runs. Empty API -> honest QG-0 fail (truly empty ticket).

src/webhooks/plane.py

@@ -261,6 +261,23 @@ async def start_pipeline(data: dict, project_id: str = ""):
     repo = proj.repo
     plane_project_id = proj.plane_project_id
 
+    # BUG 1: Plane's issue.updated webhook (status change -> In Progress) sends
+    # only the CHANGED fields, so description / description_stripped are usually
+    # empty here even though the issue HAS a description. If the payload's
+    # description is missing/too short, pull the full one from the Plane issue
+    # detail API (same GET endpoint + shared token already used by
+    # fetch_issue_sequence_id) before QG-0 runs. If the API is also empty, QG-0
+    # legitimately fails (truly empty ticket).
+    if not description or len(description.strip()) < 20:
+        from ..plane_sync import fetch_issue_description
+        fetched = fetch_issue_description(plane_id, plane_project_id)
+        if fetched and len(fetched.strip()) >= len(description.strip()):
+            description = fetched
+            logger.info(
+                f"start_pipeline: pulled description from Plane API for {plane_id} "
+                f"({len(description.strip())} chars)"
+            )
+
     # QG-0 validation (hard gate on pipeline start)
     errors = _qg0_errors(name, description)
     if errors: