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/mcp/server.py

@@ -200,7 +200,7 @@ _WRITE_TOOLS = frozenset({
     "merge_snippets", "unmerge_snippet",
     "create_process", "update_process", "delete_process",
     "classify_shapes", "classify_shapes_by_rule", "confirm_shape_proposals",
-    "refresh_pattern_coverage", "move_shapes",
+    "refresh_pattern_coverage", "move_path",
     # design systems
     "create_design_system", "update_design_system", "delete_design_system",
     "create_design_token", "update_design_token", "delete_design_token",