fix(ci): restore v0.1.{run_number} release tags and drop prerelease flag for main builds

[Copilot]

The electron branch merge replaced the original v0.1.{run_number} non-prerelease tagging scheme with main-{run_number} prereleases, breaking the per-build release cadence established by the Tauri-era CI.

Changes

• Tag format: main-{run_number} → v0.1.{run_number} for main branch builds, restoring the v0.1.173-style releases
• Prerelease flag: Removed github.ref == 'refs/heads/main' from the condition — prerelease is now solely contains(github.ref_name, '-'), so stable main builds and unadorned v* tags produce full releases; only tags like v1.0.0-beta are marked pre-release
• Release name: Dropped the explicit name: field — defaults to the tag name, matching prior behavior

# Before
tag_name: ${{ github.ref == 'refs/heads/main' && format('main-{0}', github.run_number) || github.ref_name }}
name: ${{ github.ref == 'refs/heads/main' && format('Main build {0}', github.run_number) || github.ref_name }}
prerelease: ${{ github.ref == 'refs/heads/main' || contains(github.ref_name, '-') }}

# After
tag_name: ${{ github.ref == 'refs/heads/main' && format('v0.1.{0}', github.run_number) || github.ref_name }}
prerelease: ${{ contains(github.ref_name, '-') }}

[Copilot]

Pull request overview

This PR restores the main-branch CI release behavior to publish stable v0.1.{run_number} releases instead of main-{run_number} prereleases.

Changes:

• Uses v0.1.{github.run_number} as the generated tag for main builds.
• Removes the explicit release name, allowing it to default to the tag.
• Marks releases as prerelease only when the ref name contains -.