feat: system-info telemetry tiles for CPU, memory, and disk (F006)

[nimat-dev]

Summary

This PR implements F006: System-info tiles (CPU / memory / disk), concluding Phase 02 (Terminal & telemetry).

Changes Included:

1. Wire Protocol (@shellmind/protocol):
   • sys.request: Client request for telemetry metrics ({ diskPath?: string }).
   • sys.metrics: Agent response containing CpuMetrics (usage percentage, cores), MemoryMetrics (used bytes, total bytes, percentage), DiskMetrics (used bytes, total bytes, percentage, mount), uptime in seconds, host info, and timestamp.
   • Registered in KnownMessage union and MessageRegistry.
2. Pure Core SysInfo Interface (@shellmind/agent):
   • ISysInfoProvider, SystemMetrics defined in packages/agent/src/core/sysinfo.ts with zero Node built-in or I/O imports.
3. Node SysInfo Adapter (@shellmind/agent):
   • NodeSysInfoProvider in packages/agent/src/adapters/sysinfo/node-sysinfo.ts calculating CPU usage deltas across sampling intervals, total/free RAM from os, and disk metrics via fs.promises.statfs('/').
   • Wired into AgentDaemon message dispatcher.
4. Mobile Client & UI (@shellmind/mobile):
   • AgentClient methods: requestSystemMetrics(), onSystemMetrics().
   • React Native component: SysInfoTiles.tsx displaying CPU, RAM, and Disk percentage bars with color-coded health states, core counts, and host/uptime pill.
   • Added stale indicator when disconnected.
   • Embedded into StatusScreen.tsx with auto-polling every 4 seconds.
5. E2E & Verification:
   • Maestro flow specification .maestro/sysinfo_flow.yaml.
   • Integration tests in packages/agent/src/agent.test.ts and packages/mobile/src/mobile.test.ts.
   • 53/53 tests passing across monorepo packages.
   • Clean architecture verified with dependency-cruiser (0 violations).

[nimat-dev]

Maker-Checker Review: F006 (System-info tiles)

1. Acceptance Criteria Verification

• Wire protocol messages: sys.request, sys.metrics registered in @shellmind/protocol.
• Core sysinfo interface ISysInfoProvider in @shellmind/agent/src/core/sysinfo.ts has 0 I/O imports.
• Node adapter NodeSysInfoProvider in @shellmind/agent/src/adapters/sysinfo/ wraps Node built-ins without extra binary dependencies.
• Agent daemon message dispatch handles sys.request and sends sys.metrics.
• Mobile client has requestSystemMetrics, onSystemMetrics.
• Mobile component SysInfoTiles.tsx displays live CPU/RAM/Disk bars and host/uptime pill.
• Edge cases handled: disk statfs fallback (null / "n/a"), disconnected stale badge, timer cleanup on unmount.
• Clean architecture: dependency-cruiser passes with 0 violations.
• 53/53 tests pass monorepo-wide.

2. Evaluation Scores

• Acceptance: 5/5
• Correctness: 5/5
• Boundaries: 5/5
• Modularity: 5/5
• Evidence: 5/5
• Average: 5.0 (PASS)

3. Decision

APPROVE. Ready for squash merge to main.