Add confidence field (0-100) to approvals and proposals

## Task Change confidence field from string (high/medium/low) to numeric scale (0-100) and add confidence tracking from different roles. ## Current State Confidence is currently stored as a string enum: `high`, `medium`, `low` ## Requirements 1. **Database change** - Convert confidence to integer (0-100) - Update proposals table - Add confidence to tickets (for worker and reviewer confidence) 2. **Track confidence from different roles**: - **Worker confidence** - When submitting work for review - **Reviewer confidence** - When approving/rejecting tickets - **Researcher confidence** - When creating proposals 3. **UI updates**: - Replace dropdown with numeric input or slider (0-100) - Show confidence in relevant places (approvals page, proposals, ticket detail) 4. **Agent prompts** - Update skills/prompts to ask agents to rate confidence on 0-100 scale: - Worker-workflow skill - provide confidence when submitting - Review-workflow skill - provide confidence when auditing - Researcher-workflow skill - provide confidence on proposals ## Migration Considerations - Map existing values to numbers: low→25, medium→50, high→75 (or similar) - Consider storing separate worker_confidence and reviewer_confidence on tickets ## Notes - Numeric scale provides more granularity than high/medium/low - Helps with prioritization and risk assessment - You (human) need to see worker and reviewer confidence when approving tickets