chore(config-audit): bump version to 4.0.0

v4.0.0 = MAJOR (Opus 4.7 era):
- New TOK scanner (Token Hotspots, 4 patterns)
- New /config-audit tokens command surface
- 8th quality area: Token Efficiency
- scanner-agent + verifier-agent migrated haiku → sonnet

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

plugins/config-audit/.claude-plugin/plugin.json

@@ -1,7 +1,7 @@
 {
   "name": "config-audit",
   "description": "Multi-agent workflow for analyzing, reporting, and optimizing Claude Code configuration across your entire machine",
-  "version": "3.1.0",
+  "version": "4.0.0",
   "author": {
     "name": "Kjell Tore Guttormsen"
   },