feat: tRPC routes for Mini device control + data

[ng]

Context

Add tRPC router for Mini endpoints, gated behind ENABLE_MINI feature flag.

Routes

mini.status

• Get current device state (level, sound, baby state, lock)

mini.control

• start / stop
• setSootheLevel(1-4)
• setLock(boolean)
• setWeaningMode(config)

mini.sessions

• list (paginated, date-filtered)
• get by ID (with soothe events)
• current (active session if any)

mini.biometrics

• sleepSummary (date range → duration, wake count, avg soothe)
• soothePatterns (which levels used most, time-of-night)
• trends (daily/weekly aggregates)

mini.settings

• get / update (sound type, volume, motion limiter, weaning)

Conditional Loading

Routes only registered when ENABLE_MINI=true at build time.

Parent

Epic: #405