feat(client-runtime): richer reconnect detail and 12h diagnostics log

[patroza]

Summary

• Show useful disconnect detail in the connection banner (WebSocket close codes like 1006 abnormal, ping timeouts) instead of only the generic disconnected. message.
• Keep reconnect titles short (Reconnecting... / Connection failed) and put the cause after a middle dot on the status line.
• Record short-lived connection diagnostics (disconnect / connect_failed / backoff / blocked) to localStorage with a hard 12-hour retention window (max 400 events), plus Effect.logWarning for console/traces.
• Fix generic diagnostics: onDisconnect was racing the browser close event and ignoring the forked Effect onPingTimeout hook, so every failure looked like t3vm disconnected. Capture SocketError (close codes) + onPingTimeout into a sink before formatting.

Root cause (Jaeger / host, 2026-07-29 storm)

Smart desktop logs showed 22× t3vm disconnects (~08:18–08:49 UTC) almost all as bare transport / t3vm disconnected. After this fix they should say t3vm ping timeout. or closed (1006 abnormal).

Guest Jaeger (t3-server-vm) during the storm:

• Live WS sessions drown in VCS status work: hundreds of runGitCommand / processRunner spans per connection; subscribeVcsStatus traces multi‑minute.
• Ticket issue itself is fast (µs–ms); one client saw HTTP websocket-ticket 10s timeout when the guest/event loop was wedged.
• Host at check time: load ~12, swap full (35G), cloud-hypervisor for t3vm ~200% CPU / 44% RAM — classic thrash → late pongs → Effect client 5s ping kills the socket → reconnect storm.

This PR makes the client truthful and inspectable. Ops follow-ups (not in this PR): guest memory pressure, VCS broadcaster fan-out, optional longer RPC ping interval.

Test plan

• Focused unit tests: disconnect formatting, diagnostics retention, presentation, supervisor, RPC session (including ping timeout + 1006 paths), cloud presentation
• vp check
• Full monorepo typecheck
• After deploy: reproduce reconnect; banner/log should show ping timeout or close code, not bare disconnected.
• DevTools t3code:connection-diagnostics:v1 retains events ≤12h