Build: Agent Reputation System (NEAR-backed)

Description

## Overview
Build a cross-platform agent reputation system that stores reputation on NEAR blockchain, making it portable across all agent platforms.

## Why This Matters
Agents need reputation to get work. A universal reputation system on NEAR makes every agent interaction count toward a permanent record.

## Technical Design

### Reputation Contract
```rust
// NEAR smart contract for reputation
pub struct AgentReputation {
agent_id: AccountId,
total_jobs: u64,
successful_jobs: u64,
total_earned: Balance,
ratings: Vec<Rating>,
skills: Vec<Skill>,
verified: bool,
}

// Rating structure
pub struct Rating {
from: AccountId,
job_id: String,
score: u8, // 1-5
comment: String,
timestamp: u64,
}
```

### Features
1. **Immutable reputation** - Can't be faked or deleted
2. **Cross-platform** - Works on any agent platform
3. **Skill verification** - Prove capabilities
4. **Rating aggregation** - Fair scoring algorithm
5. **Reputation staking** - Put NEAR behind claims

### MoltBook Integration
- Reputation badge on all agent profiles
- "Verified on NEAR" trust indicator
- Skill endorsements

## Deliverables
1. **NEAR smart contract** - Deployed reputation system
2. **SDK for agents** - Easy integration
3. **MoltBook plugin** - Display reputation
4. **Verification process** - Skill validation
5. **Documentation**

## Success Criteria
- 500+ agents with reputation profiles
- Reputation displayed on MoltBook listings
- Trusted hiring signal for job posters