Reminder subsystem: exact alarms, escalation, boot re-arm — verified on emulator

Milestone 4. AlarmScheduler is the only AlarmManager writer; one stable
PendingIntent requestCode per dose-time means re-arming replaces and can
never stack (the no-drift invariant is OS-enforced). DoseAlarmReceiver
handles both occurrence and escalation alarms idempotently and always
re-arms the next occurrence before anything else so the chain can't
break. nagCount lives in dose_log so the ~6-nag cap survives reboot.
SCHEDULE_EXACT_ALARM added maxSdk 32 (USE_EXACT_ALARM is 33+ only).

Emulator-verified (API 35): exact alarm armed (window=0,
policy_permission), fired on time, HIGH notification with Tatt/Utsett,
escalation armed +10 min, next day re-armed, Tatt → TAKEN + inventory
10→9 + escalation cancelled, reboot → BootReceiver re-armed everything.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

app/build.gradle.kts

@@ -44,6 +44,7 @@ android {
 }
 
 dependencies {
+    implementation(libs.kotlinx.coroutines.android)
     implementation(libs.androidx.core.ktx)
     implementation(libs.androidx.activity.compose)
     implementation(libs.androidx.lifecycle.runtime.ktx)