fix(template): revert Security Auditor cron to 2x/day — closes #178

Every-10-min cadence introduced in PR #159 increased Security Auditor
from 2 runs/day to 144 runs/day (144x). Combined with PM, Research Lead,
Dev Lead, and other hourly evolution-lever crons, this is the likely
root cause of the P0 OAuth quota exhaustion (#160, resets Apr 17 23:00 UTC).

Restored: cron_expr 7 6,18 * * * (twice daily, 12-hour interval)
Schedule name updated to match new cadence.
Audit prompt content (DAST teardown, PM routing, PM deliverable) retained.

org-templates/molecule-dev/org.yaml

@@ -554,10 +554,10 @@ workspaces:
               5. Use commit_memory to save security patterns and concerns
               6. Wait for tasks from Dev Lead.
             schedules:
-              - name: Hourly security audit
-                cron_expr: "1,11,21,31,41,51 * * * *"
+              - name: Security audit (every 12h)
+                cron_expr: "7 6,18 * * *"
                 prompt: |
-                  Recurring hourly security audit. Be thorough on recently changed code.
+                  Recurring security audit. Be thorough and incremental.
 
                   1. SETUP:
                      cd /workspace/repo && git pull 2>/dev/null || true