refactor: flatten plugin directory into repo root

Move all plugin content (skills, hats, hooks, lib, schemas, workflows)
from plugin/ to the repo root. The .claude-plugin/ directory at root
now contains plugin.json, hooks.json, and marketplace.json together.

Marketplace path updated from "plugin" to ".".
No CLAUDE_PLUGIN_ROOT references changed — they resolve automatically.

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

Author: jwaldrip

plugin/.claude-plugin/hooks.json .claude-plugin/hooks.jsonplugin/.claude-plugin/hooks.json renamed to .claude-plugin/hooks.json

@@ -15,7 +15,7 @@
       "source": {
         "source": "git-subdir",
         "url": "TheBushidoCollective/ai-dlc",
-        "path": "plugin"
+        "path": "."
       },
       "category": "Pattern",
       "keywords": [