feat: add Feiling as a built-in v2 pet

[bobleer]

Summary

Adds Feiling (绯翎) as the second built-in pet. Her name combines crimson and feather imagery to evoke Bifang. The default blue-golden cat remains first, and all existing pet IDs and saved selections are preserved.

Feiling has a smaller, softly oval face, silver hair, a black-and-ivory bell skirt, and tiny short legs. Her OpenBitFun ornaments have rounded six-sided outer outlines and rounded six-sided hollow centers. The transparent lossless v2 atlas provides nine standard animation states and 16 clockwise pointer-look directions using the existing renderer.

Type and Areas

Feature / visual asset; Web UI built-in pet catalog and packaged assets.

Motivation / Impact

Makes the character available without a manual import. The stable package ID and paths retain saved selections when its display name changes. The earlier OpenBitFun Bifang preset remains available. No host commands, protocol changes, or settings migrations are introduced.

Verification

• Companion catalog, compatibility, and sprite contract tests: 3 files, 9 tests passed.
• pnpm run check:web passed, including type, typography, Appearance, and theme gates; existing non-blocking Appearance warnings remain.
• pnpm run i18n:audit passed with zero warnings.
• V2 atlas validation passed: 1536×2288 RGBA, all required cells present, zero errors or warnings. One deterministic chroma cleanup preserved alpha.
• Final visual review covered all 57 standard frames, all 9 animation sequences, the 16-pose look loop and preview. Three isolated blind reviews classified all 28 axes correctly by majority; the four cardinal directions were unanimous. Mild near-vertical lateral cues and posture variation were accepted in the coherent loop.
• Vite static-serving smoke checks passed: manifest, atlas and preview returned HTTP 200, correct MIME types, and byte-for-byte parity.
• Repository hygiene, git diff --check and Git blob-size checks passed. The atlas is 2,920,246 bytes, below 5 MiB.

Only local tests and asset previews were exercised. No live remote-workspace, remote-control, peer-device, or detached-dispatch session was exercised; the change adds a bundled frontend preset without changing those runtime paths.

Reviewer Notes

AI-assisted artwork and implementation; lightly tested at product level, with focused automated checks and sprite QA. Temporary generation prompts, source strips, and QA scratch files are excluded from the PR.

Checklist

• Focused change without secrets, temporary prompts, scratch files, or unrelated artifacts.
• Relevant verification is recorded above.
• User-facing strings and owning documentation are updated.