Add branches filter to merge_group trigger in all CI workflows

Co-authored-by: nhorton <204146+nhorton@users.noreply.github.com>

Author: Copilot

.github/workflows/cla.yml

@@ -8,6 +8,7 @@ on:
     branches: [main]
   # Run in merge queue but skip the step (shows as passing check)
   merge_group:
+    branches: [main]
   workflow_dispatch:
 
 # Explicitly set permissions for the workflow

.github/workflows/claude-code-test.yml

@@ -14,6 +14,7 @@ on:
     branches: [main]
   # Run in the merge queue to validate before merging
   merge_group:
+    branches: [main]
 
 # Ensure only one instance runs at a time per PR/branch
 concurrency:

.github/workflows/validate.yml

@@ -4,6 +4,7 @@ on:
   pull_request:
     branches: [main]
   merge_group:
+    branches: [main]
   workflow_dispatch:
 
 # Minimal permissions for this workflow