ci: add stage 9 validation workflow

[ArcueidMP]

Summary

• Add a minimal Windows GitHub Actions workflow for non-GUI v0.1 validation
• Run JS/TS typecheck and build checks
• Run Python image-pipeline compile and unittest checks
• Record the Stage 9.2 manual E2E smoke pass in docs/dev-log.md
• Add a short README note clarifying CI scope

Scope

Included:

• .github/workflows/ci.yml
• README CI/testing note
• dev-log source-of-truth update for Stage 9.2 and Stage 9.3

Intentionally excluded:

• Electron GUI smoke in CI
• Maker or Runtime dev-server launch in CI
• installer creation
• GitHub Release binary creation
• release publishing
• zip export
• persistent settings
• Runtime launch-from-Maker
• rembg
• system tray
• multi-pet support
• plugin support
• new animation features

Stage 9.2 manual smoke

Manual E2E smoke passed on Windows for:

• Maker transparent PNG selection
• output folder selection
• pet package export
• generated pet.json, spritesheet.png, and preview.gif
• pet.json referencing spritesheet.png
• Runtime launch
• Runtime right-click menu
• Load Pet...
• generated pet display
• visible animation advancement
• drag
• Reset Position
• Always on Top toggle
• Exit

No bugfix PR was needed from the smoke run.

Verification

Local verification:

• git diff --check
• corepack pnpm typecheck
• corepack pnpm build
• corepack pnpm --filter @autopet/image-pipeline typecheck
• corepack pnpm --filter @autopet/image-pipeline test
• .\.venv\Scripts\python.exe -m compileall packages\image-pipeline\autopet_image_pipeline
• .\.venv\Scripts\python.exe -m unittest discover -s packages\image-pipeline

GitHub Actions:

• CI workflow run is green