test(live-atc): cover the wait auto-tune actually depends on

The decision to tune was tested; the three seconds between announcing it and
doing it were not, and that gap is where the feature can go wrong — it is the
only window in which the radio moves on its own.

Moves the scheduling into a testable unit and wires the composable to it, so
the tested code is the code that runs. Covered: nothing is announced when no
change is due, the change is announced immediately but made only after the
delay, and it is dropped when the pilot tuned the radio themselves, when the
session ended, and when a second handoff superseded it — the last of which would
otherwise have tuned to a stale frequency.

Leaving the flight or unmounting now cancels a pending change explicitly rather
than relying on the fire-time guards to notice.

app/composables/useLiveAtcSession.ts

@@ -11,7 +11,7 @@ import useCommunicationsEngine from '../../shared/utils/communicationsEngine'
 import { generateGermanRegistration } from '../../shared/utils/registration'
 import { gateTransmission } from '../../shared/utils/transmissionGate'
 import { silenceWindowFor } from '../../shared/utils/silenceTimer'
-import { planAutoTune } from '../../shared/utils/autoTune'
+import { createAutoTuneScheduler } from '../../shared/utils/autoTune'
 import {
   isSimControlMatch,
   isSimControlRejection,
@@ -199,58 +199,43 @@ export function useLiveAtcSession(
   // planAutoTune): the two cases that must NOT tune — a frequency readback that
   // was wrong, and one not yet given — both leave the session on a state that
   // still expects the frequency already dialled in, so nothing is due.
-  let autoTuneTimer: ReturnType<typeof setTimeout> | null = null
+  const autoTune = createAutoTuneScheduler({
+    announce: (text) => {
+      // Announce before changing, never after: the pilot has to be able to
+      // follow what their own radio just did.
+      scheduleControllerSpeech(text)
+      appendLogEntry('system', text, currentState.value?.id ?? '', {
+        frequency: frequencies.value.active,
+      })
+    },
+    tune: (frequency) => {
+      // Prefer the airport's own entry so the label and the engine's notion of
+      // the position come along; fall back to a bare entry for an invented one.
+      const known = airportFrequencies.value.find(
+        (entry: any) => normalizedFrequencyValue(entry.frequency) === normalizedFrequencyValue(frequency),
+      )
+      pmLog.info('AUTO-TUNE tuning →', frequency)
+      setActiveFrequencyFromList(known ?? {
+        type: '', label: '', frequency, source: 'openaip',
+      } as any)
+    },
+    currentSessionId: () => backendSessionId.value || null,
+    currentActive: () => frequencies.value.active,
+    onCancelled: (reason) => pmLog.info('AUTO-TUNE dropped —', reason),
+  })
 
   function clearAutoTune() {
-    if (autoTuneTimer) {
-      clearTimeout(autoTuneTimer)
-      autoTuneTimer = null
-    }
+    autoTune.cancel()
   }
 
   function scheduleAutoTune() {
-    clearAutoTune()
-    const plan = planAutoTune({
+    const plan = autoTune.schedule({
       enabled: autoTuneEnabled.value,
       active: frequencies.value.active,
       expected: expectedFrequencyForState(),
       accepted: acceptedFrequenciesForState(),
     })
-    if (!plan) return
-
-    // Announce before changing, never after: the pilot has to be able to follow
-    // what their own radio just did.
-    scheduleControllerSpeech(plan.announcement)
-    appendLogEntry('system', plan.announcement, currentState.value?.id ?? '', {
-      frequency: frequencies.value.active,
-    })
-
-    const sessionAtArm = backendSessionId.value
-    const activeAtArm = frequencies.value.active
-    pmLog.info('AUTO-TUNE armed →', plan.frequency, `in ${plan.delayMs}ms`)
-
-    autoTuneTimer = setTimeout(() => {
-      autoTuneTimer = null
-      // The session ended or a new one started while we waited.
-      if (backendSessionId.value !== sessionAtArm) {
-        pmLog.info('AUTO-TUNE dropped — session changed')
-        return
-      }
-      // The pilot reached for the radio themselves; theirs wins.
-      if (frequencies.value.active !== activeAtArm) {
-        pmLog.info('AUTO-TUNE dropped — pilot tuned manually')
-        return
-      }
-      // Prefer the airport's own entry so the label and the engine's notion of
-      // the position come along; fall back to a bare entry for an invented one.
-      const known = airportFrequencies.value.find(
-        (entry: any) => normalizedFrequencyValue(entry.frequency) === normalizedFrequencyValue(plan.frequency),
-      )
-      pmLog.info('AUTO-TUNE tuning →', plan.frequency)
-      setActiveFrequencyFromList(known ?? {
-        type: '', label: '', frequency: plan.frequency, source: 'openaip',
-      } as any)
-    }, plan.delayMs)
+    if (plan) pmLog.info('AUTO-TUNE armed →', plan.frequency, `in ${plan.delayMs}ms`)
   }
 
   // Guards the ATC reply (log entry + TTS) against being applied twice for the
@@ -853,6 +838,10 @@ export function useLiveAtcSession(
   }
 
   const backToSetup = () => {
+    // Leaving the flight: a pending frequency change belongs to a session that
+    // no longer exists.
+    clearSilenceTimer()
+    clearAutoTune()
     currentScreen.value = 'login'
     selectedPlan.value = null
     persistSelectedPlan(null)
@@ -946,7 +935,10 @@ export function useLiveAtcSession(
     }
   }
 
-  onUnmounted(clearSilenceTimer)
+  onUnmounted(() => {
+    clearSilenceTimer()
+    clearAutoTune()
+  })
 
   return {
     clearSilenceTimer,