feat: xelqor — composable DeFAI strategy marketplace, MCP pipeline composer, ERC-4626 vaults

[0xbobzilla]

## Summary
Adds the Xelqor skill — a composable DeFAI strategy marketplace where agents can browse,
compose, simulate, fork, and invest in MCP-powered strategy pipelines across 18+ chains.

## What agents can do with this skill
- Browse and filter the strategy marketplace (APY, TVL, Sharpe, risk, category)
- Compose pipelines via AI Builder (plain-English intent → MCP nodes) or Manual Composer
- Fork existing strategies and modify node parameters
- Simulate pipeline execution — get APY estimate, Sharpe, max drawdown, risk score
- Invest capital into strategies via ERC-4626 vaults
- Query live protocol data (TVL, APY) from DeFiLlama
- Export pipelines as YAML for publishing

## Key APIs
- `/api/mcp` — JSON-RPC 2.0 proxy to HeyAnon agent (x402 payment per call)
- `/api/execute` — SSE-streamed pipeline simulation
- `/api/protocol-data` — DeFiLlama live APY/TVL

## Networks
18+ including Ethereum, Base, Arbitrum, Optimism, Polygon, Solana, Hyperliquid

## Links
- App: https://xelqor.xyz/dapp/composer
- Marketplace: https://xelqor.xyz/dapp/marketplace