chore: rename default branch from master to main

Update CI and deploy workflow triggers to reference main branch.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: dpwanjala

.github/workflows/ci.yml

@@ -1,7 +1,7 @@
 name: CI
 on:
   push:
-    branches: [master]
+    branches: [main]
   pull_request:
 
 env:

.github/workflows/deploy-site.yml

@@ -2,7 +2,7 @@ name: Deploy Site
 
 on:
   push:
-    branches: [master]
+    branches: [main]
     paths: ['web/**']
   workflow_dispatch: