fix(ci): disable runner-health cron trigger — runner permanently offline

Removes schedule: */15 * * * * trigger that was generating ~96 issues/day
due to RUNNER_NAME env var conflict with GitHub Actions built-in variable.
Retains workflow_dispatch for portfolio demonstration purposes.

Fixes CIAP-01

Author: OgeonX-Ai

.github/workflows/runner-health.yml

@@ -1,8 +1,6 @@
 name: Runner Health Monitor
 
 on:
-  schedule:
-    - cron: "*/15 * * * *"
   workflow_dispatch:
 
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