perf(app): reduce box connection latency and background work

[frahlg]

Summary

• send the first telemetry subscription with hello when the box supports it, with a legacy fallback
• request 1 Hz while visible and 0.2 Hz while hidden
• drop expected Noise authentication and replay failures from other app sessions without throwing or logging a stack
• pause hidden History and Energy work, keep shown Energy data, and catch up when visible
• combine history chunk renders with requestAnimationFrame
• materialize stored snapshots only when their 15-second write is due
• skip unchanged Power Now diagram updates
• add local relay, Noise, handshake, and snapshot marks and counters; no data leaves the device

Measured impact

The paired box PR provides the wire and box-side changes.

• hidden lane-0 traffic falls by 80%, from 1 Hz to 0.2 Hz
• at the fixed 512-byte frame plus 24-byte Noise overhead, that avoids about 35.3 MiB per hidden client per day before WebSocket and TLS overhead
• an updated app and box save one post-Noise round trip before the first snapshot
• hidden History and Energy views stop requesting or assembling history until visible
• repeated history chunks cause at most one render per animation frame
• foreign relay frames no longer create one exception and stack log per frame on each unrelated app session

Compatibility

• hello.sub and hello_ok.subscribed are optional
• when the box omits the acknowledgement, the app sends the old separate sub message
• old apps still work with the updated box
• the simulator supports both paths
• visibility changes update cadence on the existing encrypted session

Checks

• npm run verify
• Svelte check: 0 errors and 0 warnings
• Vitest: 853 passed, 1 skipped across 90 files
• production Vite build
• two real Noise sessions against one relay/box test
• protocol contract copies match byte for byte
• shared UI token check passes with no drift
• local simulator browser check on desktop and 390 x 844 mobile views; no console errors
• independent code review found no remaining P0, P1, or P2 issue

Proof limits and follow-ups

• Chrome DevTools tracing was unavailable in this environment, so this PR makes no Core Web Vitals, phone CPU, or live relay latency claim
• the relay still broadcasts encrypted box frames to every app stream; this PR removes the client exception and logging cost, not that bandwidth
• directed relay routing needs a separate wire change that does not expose session identity
• a LAN or WebRTC carrier needs a separate threat model, discovery design, and measured fallback

Companion box and on-box dashboard PR: srcfl/ftw#894

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Status	Name	Latest Commit	Updated (UTC)
✅ Deployment successful! View logs	ftw-webapp	4fb9f53	Aug 11 2026, 06:42 AM

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Clear paused history when switching homes

When a user accepts an invitation to a different box while viewing another tab after History has already mounted, App.svelte's onPaired() reuses the existing SiteStore, HistoryStore, and nested EnergyStore. This guard prevents either store from refreshing or invalidating its old data while inactive, so opening History initially displays the previous household's chart and totals; if the new box is unreachable, that cross-home data remains indefinitely. Invalidate the retained History/Energy state when siteId changes even while the panel is inactive.

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