chore(ci): Update workflows to target main branch only

- Remove aot_monorepo_compat from workflow triggers
- Simplify branch targeting for all CI/CD workflows
- Maintain workflow_dispatch for manual triggers

WORKFLOWS UPDATED:
- dart.yml: CI runs on main branch only
- enhance-release-pr.yml: Enhance PRs to main only
- release-please.yml: Release automation on main only

REASON:
- Aligns with standard git workflow (feature branches → main)
- aot_monorepo_compat will merge to main via PR #8
- Reduces workflow complexity and CI noise

Author: tsavo-at-pieces

.github/workflows/dart.yml

@@ -1,11 +1,11 @@
 name: Dart
 
 on:
-  # Run CI on pushes to main/aot_monorepo_compat, and on PRs against them.
+  # Run CI on pushes to main and on PRs against main.
   push:
-    branches: [main, aot_monorepo_compat]
+    branches: [main]
   pull_request:
-    branches: [main, aot_monorepo_compat]
+    branches: [main]
   workflow_dispatch:
 
 # Cancel in-progress runs when new commits are pushed

.github/workflows/enhance-release-pr.yml

@@ -5,7 +5,6 @@ on:
     types: [opened, synchronize, reopened]
     branches:
       - main
-      - aot_monorepo_compat
 
 # Cancel in-progress runs when a new commit is pushed to the same PR
 concurrency:

.github/workflows/release-please.yml

@@ -19,7 +19,6 @@ on:
   push:
     branches:
       - main
-      - aot_monorepo_compat
 
 # Only one Release Please run per branch at a time
 concurrency: