feat(6243): a directory moved in the tree keeps its shape judgments

Ledger rows are keyed by path, so after a directory moves the next sync
marks every judged row vanished and lists the same shapes again, unjudged.
move_shapes(project_id, from_path, to_path) re-keys the rows under one path
to the other, in every repo of the project, keeping each row's judgment,
uses edges and history and adding a `moved` event that records the path it
left. A row already at the target is replaced when nobody judged it; a
judged one stands, and the old row is reported in `kept`.

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

plugin/skills/shape-accounting/SKILL.md

@@ -41,6 +41,13 @@ row carries a status:
    nothing. Rows, never prose — a consumer list in a note or verification
    detail cannot be sorted, queried, or diffed.
 
+Rows are keyed by repo and path, so a move in the tree is a move in the
+ledger. When a file or directory moves, run `move_shapes(project_id,
+from_path, to_path)` before the next refresh. For a repo renamed on its
+forge, run `bind_repo(new_url, project_id, moved_from=old_url)`. Otherwise
+the refresh marks every judged row vanished and lists the same shapes again,
+unjudged.
+
 ## The writer judges; audits check that it happened
 
 The ledger is filled from your answers, given while you still know them. When
@@ -157,8 +164,8 @@ Three questions the ledger answers mechanically:
   it), `variant` with the why if the departure is deliberate. The write-path
   hint asks the same question in-band the moment such a shape is written.
 - **History** — `shape_history(project_id, path, symbol?)`: the current rows
-  plus every `classified` / `vanished` / `reappeared` / `drifted` event with
-  its commit — "instance of #N from <date>, re-judged variant of #M because
+  plus every `classified` / `vanished` / `reappeared` / `drifted` / `moved`
+  event with its commit — "instance of #N from <date>, re-judged variant of #M because
   R, vanished at C". Rows, not recollection.
 - **Recheck** — `list_shapes(project_id, flag="recheck")`: judged
   instances/variants whose body changed since judged. The judgment stands;