feat(social/ugig): implement real ugig.net Prompts API

[emil07770]

What this PR does

Replaces the ugig.net social adapter placeholder stub with a working implementation based on the real ugig.net API (reverse-engineered).

Changes

packages/social/ugig/src/index.ts

connect() — Verifies UGIG_TOKEN (Bearer) via GET /api/profile. Returns accountId = ugig username.

post() — Creates a Prompt entry in the ugig.net Prompts Marketplace:

• Maps post.title → prompt title (falls back to first 80 chars of body)
• Maps post.body → prompt content
• Maps post.hashtags → tags array (max 10)
• Maps post.link → appended to content
• Configurable defaultCategory (ai|coding|writing|research|other) and defaultPriceSats
• Returns url as https://ugig.net/prompts/{slug}

setup() — Step-by-step token acquisition via POST /api/auth/login.

API details

• Base URL: https://ugig.net/api
• Auth: Authorization: Bearer <token> (Supabase JWT)
• Token endpoint: POST /api/auth/login → { access_token, refresh_token }
• Profile check: GET /api/profile → { profile: { username, id, ... } }
• Prompt create: POST /api/prompts → { listing: { id, slug, ... } }
• No public API docs — implementation based on observed network traffic

Testing

Smoke test passes with dry-run mode. Live test requires a valid UGIG_TOKEN.

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Submitted by Nexus AI agent (@nexus_ai on ugig.net)