feat(6243): move_path carries a moved path's snippets with its shapes

Snippet locations are keyed by path too, so a snippet recorded under a
moved directory reads `missing` at its next check. The tool is now
move_path(project_id, from_path, to_path). It moves the ledger rows as
before, and re-paths the project's snippet locations under from_path
through update_snippet, so each body and its indexed mirror stay one
record. A snippet the caller can only read is listed in
snippets_read_only. The tool refuses only when nothing at all is recorded
under from_path. The path test is the one snippets already uses
(_path_touches), and the plugin version is minted for the skill edit.

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

src/grimoire/services/shape_ledger.py

@@ -170,10 +170,6 @@ async def sync_repo_shapes(
         await session.commit()
 
 
-def _under(path: str, prefix: str) -> bool:
-    return path == prefix or path.startswith(prefix + "/")
-
-
 async def move_shapes(
     user_id: int, project_id: int, from_path: str, to_path: str,
 ) -> dict:
@@ -193,12 +189,13 @@ async def move_shapes(
     from sqlalchemy import or_
 
     from grimoire.services import access
+    from grimoire.services.snippets import _path_touches
 
     old = (from_path or "").strip().strip("/")
     new = (to_path or "").strip().strip("/")
     if not old or not new:
         raise ValueError("from_path and to_path are both required")
-    if _under(old, new) or _under(new, old):
+    if _path_touches(old, new) or _path_touches(new, old):
         raise ValueError(f"`{old}` and `{new}` overlap; move to a path outside the source")
     if not await access.can_write_project(user_id, project_id):
         raise ValueError(f"project {project_id} not found or no write access")
@@ -213,10 +210,8 @@ async def move_shapes(
         # LIKE reads `_` as a wildcard; the prefix test is the real filter.
         sources = [
             r for r in (await session.execute(beneath(old))).scalars().all()
-            if _under(r.path, old)
+            if _path_touches(old, r.path)
         ]
-        if not sources:
-            raise ValueError(f"project {project_id} has no shapes under `{old}`")
         targets = {
             (r.repo_key, r.path, r.symbol, r.kind): r
             for r in (await session.execute(beneath(new))).scalars().all()