docs(6206): the remaining models, routes, mcp/tools/repos and config comments drop citations

A shipped tool docstring (mcp/tools/repos bind_repo) cited this instance's
"rule 1: dev is home"; it now says what a dev-branch project should do.
routes/knowledge, routes/tasks, routes/systems and models/retrieval_log state
the property each guards rather than the bug that once broke it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/scribe/routes/tasks.py

@@ -242,9 +242,8 @@ async def update_task_route(task_id: int):
     if "tags" in data:
         fields["tags"] = data["tags"]
 
-    # Re-filing a task's kind. The editor has always SENT this field and the
-    # route silently dropped it — reporting "Task saved" and reverting on the
-    # next load (#3129). Validated at the same layer as status and priority so
+    # Re-filing a task's kind. The editor sends this field; dropping it would
+    # report "Task saved" and revert on the next load. Validated at the same layer as status and priority so
     # an unrecognised value is a 400 rather than a database CHECK violation.
     if "kind" in data:
         try: