fix(#570): scope Codex leak scanner to manifest + replace bare ~/.claude refs

* fix(#570): scope Codex leak scanner to manifest, replace bare ~/.claude refs

Two root causes:
- scanForLeakedPaths walked entire ~/.codex tree, flagging pre-existing
  unrelated files; now reads gsd-file-manifest.json to scope scan to
  GSD-owned artifacts only
- convertClaudeToCodexMarkdown replaced ~/\.claude/ (slash form) but not
  bare ~/\.claude\b; gsd-debugger.toml and gsd-surface/SKILL.md examples
  slipped through; bare word-boundary replacement now added
- writeManifest tracked agents/gsd-*.md but Codex installs .toml files;
  manifest now also records .toml agent files so the scoped scanner covers them

Closes #570

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* chore: add changeset fragment for #570

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

.changeset/sunny-lynx-rally.md

@@ -0,0 +1,5 @@
+---
+type: Fixed
+pr: 570
+---
+Codex leak scanner now reads gsd-file-manifest.json to scope path checks to GSD-owned files only; bare ~/.claude (no trailing slash) is now replaced in converted Codex markdown; writeManifest now records agents/gsd-*.toml so the manifest-scoped scanner covers them