revert: restore gsd-cursor-pre-tool.js dead imports (golden parity)

Reverts the LOW-severity dead-import removal (require('fs')/require('path'))
that changed the file hash and broke 9 golden-install-parity fixtures. The
golden test computes per-runtime hashes of installed hook files; regenerating
all 9 fixtures for a cosmetic cleanup is disproportionate. Dead imports are
harmless (Node caches built-in requires) — noted as a follow-up nit.

hooks/gsd-cursor-pre-tool.js

@@ -22,6 +22,9 @@
 
 'use strict';
 
+const fs = require('fs');
+const path = require('path');
+
 const WRITE_TOOL_RE = /write|edit|replace|create|delete|remove|append|apply|patch|insert|mkdir/i;
 const PATH_KEY_RE = /^(path|file|file_?path|filepath|target_?path|target|dir|directory|uri|filename)$/i;
 const PLANNING_PATH_RE = /(^|[\\/])\.planning([\\/]|$)/;