release: v5.12.0 — "Auto-calibration" (B8b)

Version-sync for the B8b model→window auto-probe shipped in cf75249:
- plugin.json 5.11.0 -> 5.12.0
- README version badge + version-history row (1296 tests)
- CHANGELOG [5.12.0] entry

Scanner count stays 16, agents 7, commands 21. No new finding ID or scanner.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.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": "5.11.0",
+  "version": "5.12.0",
   "author": {
     "name": "Kjell Tore Guttormsen"
   },