fix(6855): the fence keeps its files where no compaction sweeps them, and builds id lists under mawk

The project a session entered now lives in grimoire-fence, which the
compaction clear never visits, and session end removes it. Arrays of ids
in a tool's input were sent as [,"3","4"] under mawk, which creates an
array element as soon as it is assigned to.

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

plugin/.claude-plugin/plugin.json

@@ -1,7 +1,7 @@
 {
   "name": "grimoire",
   "description": "Grimoire for Claude Code: connects the grimoire MCP server, adds the hooks that deliver live project state and relevant records at the right moment, ships the shared client-neutral Grimoire skills (using-grimoire, writing-plans, reporting-back, systematic-debugging, verification, brainstorming, reusing-code, shape-accounting, family-canon), and syncs your saved Grimoire Processes as skills (/grimoire:sync).",
-  "version": "2026.11.05.0245",
+  "version": "2026.11.05.0251",
   "author": {
     "name": "Bryan Van Deusen"
   },