Add realtime server monitoring page

[Derrickkoko1234]

Summary

Adds a realtime server monitoring view to Aeroplane, modeled on Dokploy/Coolify's monitoring dashboards. It shows live usage of the machine running Aeroplane.

Reachable from a new owner-only Monitoring link in the projects header (/monitoring).

What it tracks

• CPU Usage — sampled CPU % across cores
• Memory Usage — used / total
• Disk Space — root filesystem via df
• Docker Disk Usage — images / containers / volumes / build cache via docker system df (donut chart)
• Block I/O — aggregated container read/write via docker stats
• Network I/O — aggregated container in/out via docker stats

Implementation

• src/server/monitoring.ts — collectMonitoringSnapshot() gathers all metrics with safe parsing/fallbacks (returns zeros/null when Docker or df is unavailable).
• src/server/index.ts — owner-only endpoints:
  • GET /api/system/monitoring — one-shot snapshot
  • GET /api/system/monitoring/stream — SSE, pushes a fresh snapshot every 2s (mirrors the existing deployment/runtime log-stream pattern, with abort cleanup)
• src/client/pages/monitoring-page.tsx + src/client/routes/monitoring.tsx — consumes the SSE stream and renders live SVG sparklines, usage meters, and a Docker-usage donut. Block/Network I/O are charted as per-interval deltas since the docker values are cumulative. No new dependencies — charts are hand-rolled SVG to match the existing dark zinc/mono theme.
• src/client/api.ts — MonitoringSnapshot type + api.monitoring().

Testing

• npm run typecheck passes
• vite build passes

🤖 Generated with Claude Code

---

Summary by cubic

Adds a real-time, owner-only Monitoring page that streams server metrics via SSE and visualizes them with live charts. This gives owners quick visibility into the Aeroplane host’s CPU, memory, disk, Docker usage, and container I/O.

• New Features
  • Owner-only Monitoring page at "/monitoring" with a new header link from Projects.
  • Endpoints: GET "/api/system/monitoring" (snapshot) and GET "/api/system/monitoring/stream" (SSE every 2s).
  • Metrics: CPU %/cores, memory used/total, root disk used/total, Docker disk breakdown (images/containers/volumes/build cache), aggregated container Block I/O and Network I/O (charted as per-interval deltas).
  • Safe fallbacks when "docker" or "df" are unavailable (returns zeros/null); owner access enforced.
  • UI uses lightweight SVG sparklines/meters and a donut chart; no new dependencies.

^{Written for commit d1cedd8. Summary will update on new commits.}