chore(apm): give bin a published description that describes it

Why: bin's marketplace description read "A place for things to be binned" — a
routing boundary sitting in the enumeration slot, phrased as a joke. It is what
a consumer sees in the marketplace listing for a plugin shipping eleven
substantive skills: research, write-docs, tdd, prototype, triage, diagnose,
improve-codebase-architecture, grill-me, grill-with-docs, zoom-out and caveman.

This is the same category error b0ef503 fixed for git and gitea, and the same
text bb9158d moved out of core's description in August — "triage, diagnosis,
architecture review" left core precisely because those skills live in bin, so
bin is where it should have landed.

Implementation notes: bin 1.1.3 -> 1.1.4, marketplace 0.4.3 -> 0.4.4, PATCH for
metadata under the per_package strategy. README's bin line mirrors the new
description. architecture.md's routing boundary is deliberately left as
"unsorted skills that have not earned a home yet" — that is still true, and it
answers a different question than the listing does.

Impact: consumer-facing. apm-pack-check-clean, check-plugin-content-sync,
check-marketplace-mirror-sync, validate-marketplace, validate-plugins and
apm-audit-ci all pass.

.github/plugin/marketplace.json

@@ -1,7 +1,7 @@
 {
   "name": "holocron",
   "description": "AI development skills for Claude Code and GitHub Copilot CLI — factory, design, implement, review, and cross-cutting workflows.",
-  "version": "0.4.3",
+  "version": "0.4.4",
   "owner": {
     "name": "Defame1297",
     "email": "defame1297@rkdr.net",
@@ -17,8 +17,8 @@
     },
     {
       "name": "bin",
-      "description": "A place for things to be binned",
-      "version": "1.1.3",
+      "description": "Cross-cutting workflow skills not yet split into a focused plugin — research, documentation, TDD, prototyping, triage, diagnosis, architecture review, and requirement grilling.",
+      "version": "1.1.4",
       "category": "Utilities",
       "source": "./plugins/bin"
     },