Remove branches filter from merge_group triggers

The merge queue creates temporary refs like gh-readonly-queue/main/pr-N-xxx.
The branches: [main] filter was preventing workflows from triggering because
the ref name doesn't match the simple "main" glob pattern.

Since merge queue is only enabled for specific branches via branch protection
rules anyway, the branches filter on merge_group events is redundant and
causes the workflows to never run.

This fixes all 4 required checks (tests, claude-code-e2e, cla-check,
validate-generation) not running in merge queue.

Author: claude

.github/workflows/cla.yml

@@ -9,7 +9,8 @@ on:
   # Run in merge queue but skip the step (shows as passing check)
   merge_group:
     types: [checks_requested]
-    branches: [main]
+    # Note: Don't use branches filter here - merge queue refs like
+    # gh-readonly-queue/main/pr-N-xxx don't match simple branch globs
   workflow_dispatch:
 
 # Explicitly set permissions for the workflow

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

@@ -15,7 +15,8 @@ on:
   # Run in the merge queue to validate before merging
   merge_group:
     types: [checks_requested]
-    branches: [main]
+    # Note: Don't use branches filter here - merge queue refs like
+    # gh-readonly-queue/main/pr-N-xxx don't match simple branch globs
 
 # Ensure only one instance runs at a time per PR/branch
 concurrency:

.github/workflows/validate.yml

@@ -5,7 +5,8 @@ on:
     branches: [main]
   merge_group:
     types: [checks_requested]
-    branches: [main]
+    # Note: Don't use branches filter here - merge queue refs like
+    # gh-readonly-queue/main/pr-N-xxx don't match simple branch globs
   workflow_dispatch:
 
 # Minimal permissions for this workflow