feat(standards): add versioning + changelog standard, release templates, and Drone version guard

Add lib page 11 (SemVer contract, pre-1.0 rule, tag==version invariant, Keep a Changelog), the releasing wiki runbook, and canonical release templates (CHANGELOG.md, VERSION). Vendor them into the MCP bundle as templates/release + release.json and expose registry://release with list/get tools. Add a changelog component to the app template. Enforce the tag<->version contract in both Drone shapes: Type A check-version and the backfill loop verify pyproject version; Type B adds a VERSION guard step.

standards/mcp/index.json

@@ -1,6 +1,6 @@
 {
   "project": "standards",
   "type": "standards",
-  "modules_count": 14,
+  "modules_count": 15,
   "source": "hand-authored"
 }