feat: add native animated pet workflow

[Gu1nBz]

Summary

• add LiveAgent-native animated pet creation, import, desktop rendering, packaging, and activation
• add native image generation/editing with adaptive JSON and SSE response parsing
• validate generated pet rows and reject mixed image display sources before installation
• provide api2img and hatch-pet built-in workflows for end-to-end pet creation

Verification

• cargo test -p liveagent --lib commands::pet
• cargo check -p liveagent --lib
• pnpm exec tsc --noEmit
• node --test test/tools/path-and-system-tools.test.mjs test/pet/runtime.test.mjs
• pnpm tauri build --debug