feat: Add Algora bounty discovery with tech_stack parsing

[gianmarcozap]

Fixes #4.

Changes made:

• Updated the API endpoint to \https://algora.io/api/bounties?status=open&limit=50\ as requested.
• Extract \ ech_stack\ dynamically by aggregating \labels, \ ags, and \language\ arrays from the payload.
• Added \ ech_stack\ as an optional array field to the \Opportunity\ type and mapped it in the
  untime_jobs\ payload.
• 
  eward_usd\ remains strictly parsed from amounts/cents or extracted via regex fallback, never invented.

Note on Acceptance Criteria 4 (API Sample):
When testing locally, \�lgora.io/api/bounties\ returned \406 Not Acceptable\ / HTML, likely due to Cloudflare bot protection blocking cURL/Node.js outside a whitelisted browser or edge function environment. The integration exactly matches the URL specified in the issue and gracefully handles nested structures.