Feat: add pool manager endpoints

[mukama]

Summary

• Add pool manager endpoints for stats, pools, miners, units, alerts, pool assignment, and power mode control
• Uses getWrkExtData with minerpool type for pool stats (matching /auth/pools pattern)
• Uses listThings for miner/unit/alert data with proper thing structure mapping
• Routes use createCachedAuthRoute/createAuthRoute helpers, no region filtering

Endpoints

Read (GET, cached)

• GET /auth/pool-manager/stats — aggregated pool stats (totalPools, totalWorkers, activeWorkers, totalHashrate, totalBalance, errors)
• GET /auth/pool-manager/pools — pool configs with hashrate, worker counts, balances, yearly history
• GET /auth/pool-manager/miners — paginated miner list with search/model filters
• GET /auth/pool-manager/units — containers grouped with miner counts and nominal hashrate
• GET /auth/pool-manager/alerts — pool-related alerts with severity levels

Write (POST, requires pool_manager:rw)

• POST /auth/pool-manager/miners/assign — assign pool config to miners via applyThings
• POST /auth/pool-manager/miners/power-mode — set power mode (low/normal/high/sleep)

Example Queries

Pool stats:

/auth/pool-manager/stats

Pool configs:

/auth/pool-manager/pools

Miners with pagination and search:

/auth/pool-manager/miners?limit=10&page=1&search=S19XP

Filter miners by model:

/auth/pool-manager/miners?model=whatsminer

Units (containers):

/auth/pool-manager/units

Alerts:

/auth/pool-manager/alerts?limit=20