v1.57.7.0 fix(ios-qa): sliding tunnel cache so device sessions survive past 30s

[sternryan]

What

Make the iOS QA daemon's device-tunnel cache a sliding idle-timeout instead of a flat 30s window, with a configurable default.

Why

getTunnel() in ios-qa/daemon/src/index.ts cached the CoreDevice tunnel for a flat 30s measured from bootstrap, and never refreshed the timer on use. A vision-driven agent loop (/ios-qa) reads a screenshot, reasons, then taps — that round trip routinely exceeds 30s. When the cache expires the daemon re-bootstraps, but re-bootstrap can't succeed against a still-running app: StateServer deletes its on-disk boot token at /auth/rotate (templates/StateServer.swift.template → removeItem(atPath: bootTokenPath)), so bootstrapTunnel fails with boot_token_unavailable until the app is cold-relaunched.

Observed live: the bridge died roughly every 30 seconds mid-session and could only recover by killing + relaunching the app on the device.

Fix

Refresh cachedTunnelAt on every cache hit (sliding idle-timeout), so an active session holds the same live tunnel and rotated bearer for as long as it keeps working. Default idle window raised to 5 min (covers reason-then-act gaps) and made configurable via GSTACK_IOS_TUNNEL_CACHE_MS. No security change — the boot token still dies at rotate; this only avoids needless re-bootstrap of a healthy tunnel.

The default bump (30s → 5min) is the debatable knob; with the sliding behavior even a short default survives active use, but the reason-then-act gap between requests is what needs the longer window. Easy to dial back if you'd prefer.

Test

Adds a regression test in daemon-integration.test.ts asserting a burst of requests bootstraps the tunnel exactly once. bun test test/daemon-integration.test.ts → 5 pass, 0 fail.

Notes

• Heads-up (pre-existing, not touched here): daemon-integration.test.ts imports afterEach at the bottom of the file, and the tailnet listener describe block errors with afterEach is not a function under bun — reproduces on main verbatim, so that block's tests don't run. Worth a separate fix (move the import to the top).
• Fork PR: eval/E2E CI jobs won't get base-repo secrets, so they'll fail on empty-env auth. The daemon test + lint don't need secrets. Move base-side if you want full CI.

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[sternryan]

Rebased onto current main to clear the conflict — the PR is now mergeable. The only conflict was a stale chore(release): v1.57.7.0 commit (main is already at 1.58.5.0), which I dropped since versioning is the maintainer's call at merge time; the actual code fix applied with zero conflicts. Branch is now a single commit touching only ios-qa/daemon/src/index.ts + its integration test. Ran the affected test locally: 5 pass / 0 fail.