ci: no automated validation for Docker/Electron/Web build artifacts

[icebear0828]

Problem

The project produces 3 build artifacts (Docker image, Electron app, Web dashboard) but CI does not validate all of them. A pre-push hook exists locally but:

1. Only runs on the developer's machine
2. New contributors / CI don't benefit from it
3. Historical incidents of src/ changes breaking Docker build or Electron packaging

Impact

Build breakage discovered late — after merge or during release, not at PR time.

Proposed fix

Add CI jobs (GitHub Actions) that run on PR:

• `npm run build` (web dashboard)
• `docker build .` (Dockerfile lint + build)
• Electron config validation (package.json + forge config)
• `tsc --noEmit` (type check)
• Native addon build check (Rust compile)