feat: expand Algora bounty discovery

[genaaredes-ui]

Resolves #4

Summary

• add a 50-item Algora discovery path with the documented endpoint and legacy console fallback
• accept legacy object/array responses and the current tRPC envelope without confusing nested data for bounties
• extract real USD rewards, technology metadata, and the raw source item while preserving null when a reward is not parseable
• keep the existing SHA-1 URL-based idempotency behavior and include tech_stack in queued payloads

Validation

• git diff --check passed
• Deno/Supabase CLI validation was unavailable in this environment
• no rewards or sample bounties are fabricated when Algora returns an error or non-JSON page

[genaaredes-ui]

For the $3 USDC Base reward, please use the same public Base payout address already provided in this PR context: 0xA02f75b4407E79374F68ef994e8441631A7cb2C1.