feat: add static OG image generator

[pntech20]

Summary

• add a build-time OG image generator using route configs and Satori/Sharp
• generate homepage and Stellar OG PNGs under public/og/
• wire the default HTML metadata and route-aware runtime metadata to the generated image paths

Comparison

Before	After

Stellar card:

Checks

• npm run build
• npm exec prettier -- --check index.html package.json scripts/og.tsx src/main.tsx src/metadata.ts src/ogRoutes.ts
• git diff --check

Closes #7

[vercel]

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[truthixify]

Heads up — we've just set up a develop branch as the integration target for all Drips × Stellar Wave contributions, and I've retargeted this PR's base from main to develop on your behalf. The diff is unchanged; nothing to do on your end.

Going forward, please branch from and target develop. We'll periodically merge develop → main as we cut releases. Thanks for contributing!