feat: add automated semantic versioning with git-semver-plugin

[adityamparikh]

Summary

• Add jmongard/git-semver-plugin for automatic version calculation from conventional commits
• Add auto-release.yml workflow for SNAPSHOT builds and changelog accumulation
• Add cut-release.yml workflow for manual release creation
• Update build-and-publish.yml to use plugin-calculated version
• Comprehensive documentation updates to WORKFLOWS.md

How It Works

Version Calculation

The plugin analyzes commits since the last tag:

• fix: → patch bump (1.0.0 → 1.0.1)
• feat: → minor bump (1.0.0 → 1.1.0)
• feat!: or BREAKING CHANGE: → major bump (1.0.0 → 2.0.0)

Release Flow

PR Merged to main
       │
       ▼
┌──────────────────────┐
│ auto-release.yml     │  SNAPSHOT build
│ Accumulates changelog│  Updates CHANGELOG.md (Unreleased section)
└──────────────────────┘

Manual "Cut Release" (when ready)
       │
       ▼
┌──────────────────────┐
│ cut-release.yml      │  Calculates version from commits
│ Creates v1.0.0 tag   │  Finalizes changelog, creates GitHub Release
└──────────┬───────────┘
           │
           ▼
┌──────────────────────┐
│ build-and-publish    │  Triggered by v* tag
│ Publishes Docker     │  to GHCR
└──────────────────────┘

New Gradle Commands

./gradlew printVersion      # Show calculated version (e.g., 1.0.0-SNAPSHOT)
./gradlew printChangeLog    # Show auto-generated changelog

Test plan

• ./gradlew printVersion returns 1.0.0-SNAPSHOT
• ./gradlew printChangeLog generates proper changelog from commits
• ./gradlew classes compiles successfully
• Verify auto-release workflow accumulates changelog on merge
• Verify cut-release workflow creates tag and GitHub Release
• Verify tag creation triggers Docker publishing

🤖 Generated with Claude Code

[adityamparikh]

@epugh @janhoy please review

[epugh]

I looked at the WORKFLOWS.md, and I think i see how to do this manually...

[epugh]

I think this is pending us getting one real release out using the apache trusted release tooling, and then we'll learn enough about how to integrate this.