feat(ci): use RELEASE_TOKEN secret for release-please

- Update checkout and release-please-action to use RELEASE_TOKEN
- Add default-branch: main and fork: false to release-please config
- RELEASE_TOKEN is a fine-grained PAT with proper permissions configured via Terraform

Author: d0ugal

.github/workflows/release-please.yml

@@ -22,14 +22,16 @@ jobs:
     - uses: actions/checkout@v5
       with:
         fetch-depth: 0
-        token: ${{ secrets.GITHUB_TOKEN }}
+        token: ${{ secrets.RELEASE_TOKEN }}
 
     - uses: googleapis/release-please-action@v4
       id: release_please
       with:
         release-type: go
         path: .
-        token: ${{ secrets.GITHUB_TOKEN }}
+        token: ${{ secrets.RELEASE_TOKEN }}
+        default-branch: main
+        fork: false
 
     # Debug info
     - name: Debug Release Info