chore(security): supported-versions matrix for 1.36.0

Mark 1.36.x as the Active line now that 1.36.0 has shipped, and retire
1.35.x. The 1.36.0 security advisories (GHSA-768w-qrh2-jjvh,
GHSA-g6v8-r577-76jm) patch 1.36.0 and backport to the 1.34.x LTS line
only, not 1.35.x, so 1.35.x is end-of-life; users should upgrade to
1.36.x. 1.34.x LTS is unchanged.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DYcuURscruaF1yNVHJHW3C

Author: andypost

SECURITY.md

@@ -6,7 +6,8 @@ FreeUnit provides security maintenance for the following versions:
 
 | Version | Supported |
 |---------|-----------|
-| 1.35.x  | ✅ Active |
+| 1.36.x  | ✅ Active |
+| 1.35.x  | ❌ EOL — upgrade to 1.36.x |
 | 1.34.x  | ✅ LTS    |
 | < 1.34  | ❌ No     |