feat(release): simplify dev versioning with stable base

- Remove dev branch from semantic-release (main only)
- Add dev-release.yml: simple X.Y.Z-dev.N bump workflow
- Update sync workflow: handle merge conflicts for version files
- Update release.yml: trigger only on main branch

Dev versions now stay at {stable}-dev.N until merged to main.
PR merge commit type (feat/fix) determines actual version bump.

.github/workflows/release.yml

@@ -2,9 +2,7 @@ name: Release
 
 on:
   push:
-    branches:
-      - main
-      - dev
+    branches: [main]
   workflow_dispatch:
 
 jobs: