Add Pigeon of the Day homepage card - #2

What changed

• add a responsive Pigeon of the Day card beside the profile
• derive one deterministic seed from the visitor's local calendar date
• show the generated pigeon in an embedded preview
• link the whole card to the full generator with the same seed
• deploy the self-contained generator as /pegeongen.html

User impact

The homepage now has a new daily pigeon in the previously empty profile space. It stacks cleanly below the profile on mobile and follows both light and dark themes.

Validation

• homepage and generator return HTTP 200 locally
• all requested local resources return HTTP 200
• desktop light, desktop dark, and 390 px viewport screenshots reviewed
• preview seed and click-through seed statically verified
• generator bundle contains no unresolved /assets/ references