feat: Agent Router — hire page at /hire

New marketplace UI where users describe a problem and get matched with AI agents:
- Hire.tsx: 3-state flow (input → ranked results → job tracking)
- 8 mock agents across 4 TTDs (code-review, documentation, data-extraction, translation)
- Keyword-based intent classification + composite scoring
- Simulated job lifecycle with status stepper
- Glassmorphism design matching existing theme
- 'Hire Agent' button in landing page nav
- /hire route in main.tsx

Author: jimmdd