refactor: split dev build into separate workflow that only runs on main

[d0ugal]

Problem

Dev builds were running for release PRs and release-please branches, which is unnecessary since release builds are handled by the release workflow.

Solution

Split the dev-build job into its own workflow file that only triggers on push to main branch. This ensures dev builds never run for:

• PRs (including release PRs)
• Release-please branches
• Any branch other than main

Changes

• Created new .github/workflows/dev-build.yml workflow
  • Only triggers on push to main branch
  • Skips release commits automatically
  • Skips documentation-only changes
• Removed dev-build and check-build-needed jobs from ci.yml
• Simplified CI workflow to focus on test, lint, build, and security

Benefits

• Clearer separation of concerns: Dev builds are isolated in their own workflow
• Impossible to run on PRs: The workflow only triggers on push to main
• Simpler CI: Main CI workflow is cleaner and easier to understand
• No more release PR builds: Release PRs can't trigger dev builds since they're not pushes to main