Use PNG for Peace Hill Studios branding

[mot-yelraf]

Summary

Use the replacement PNG for the Peace Hill Studios logo in System Settings and replace both repository SVG copies. The served image decreases from 13.2 MB to 464 KB while retaining its existing display size and versioned URL. Bump the app version to v0.26.251.6.

Verification

• npm run validate:pr: all 9 Playwright Chromium tests passed on macOS with Python 3.13.9.
• git diff --check: passed.
• Verified the source and served PNG copies match, are 512 × 512, and no old SVG references remain.
• Used the isolated fixture host; no MQTT broker or direct hardware was involved.

Contributor checklist

• This pull request is focused on one logical change.
• Existing browser tests pass; no new tests needed for this asset replacement.
• No canonical documentation changes needed for this asset replacement.
• I did not commit credentials, private runtime configuration, databases, or logs.
• Compatibility-sensitive MQTT, settings, switch identity, and persistence behavior is preserved.

Maintainer verification

• Remote checks pass: Python compile (3.11 and 3.13) and regression tests with coverage floor.
• npm run validate:pr passes on a trusted host.
• Unverified areas are recorded below.

Residual risk or unverified areas

The logo was not separately visually inspected in the System Settings modal. Hardware, MQTT, and onboarding were not exercised; this change only replaces a static branding asset and its template reference.