Show device temperatures on the performance overlay

Ported from ARMSX2. Android has no supported API for SoC temperatures --
HardwarePropertiesManager is gated behind the signature-level DEVICE_POWER --
so the only route is the thermal sysfs, which is readable without permission
on essentially every device but is not a contract: zone count, order, naming
and even the unit are all vendor-specific. So the app discovers zones once by
name, tolerates every failure by having no reading, and never displays a value
it could not actually read. A device that exposes nothing shows nothing, which
is a normal outcome rather than an error.

The core cannot read these and should not learn how, so the app pushes them in
through _rpcsx_setThermals into atomics beside the overlay. The overlay line is
appended after the detail-level switch, the same way the frame generation line
is, so all four levels get it without their format strings and positional
arguments having to agree.

The sentinel is -1000.0f on both sides. ARMSX2 spells the Kotlin half
Float.MIN_VALUE, which in Kotlin is the smallest POSITIVE float (1.4e-45) and
so arrives as a real temperature of 0 degrees rather than as absent; worth
correcting there too.

Default on, poll interval configurable 1-5s (default 2s) since sensor overhead
was the concern raised when this was asked for. No realtime option: a
temperature that moves slower than a second is not worth the syscalls.

android/armsx3-ui/app/src/main/java/com/armsx2/i18n/I18n.kt

@@ -905,6 +905,10 @@ val EN: Map<String, String> = mapOf(
     "pad.rightStickFeel.title" to "Right Stick Feel",
     "pad.players.help" to "The PS3 has seven controller ports and no multitap, so up to seven pads work with no setup. Connect them before launching — the order they first press a button in is the order they are assigned.",
     "pad.rumble.description" to "Master switch for controller rumble and the device's built-in vibration. Turn off to silence all haptics.",
+    "overlay.toggle.temps" to "Device temperatures",
+    "overlay.toggle.temps.description" to
+        "Show CPU, GPU and battery temperature on the performance overlay. Not every device exposes these \u2014 one that doesn't simply shows nothing.",
+    "overlay.tempInterval.label" to "Temperature poll interval",
     "pad.rumble.label" to "Rumble / Vibration",
     "pad.rumblePhone.label" to "Vibrate the phone",
     "pad.rumblePhone.description" to

android/armsx3-ui/app/src/main/java/com/armsx2/runtime/MainActivityRuntime.kt

@@ -2158,6 +2158,9 @@ open class MainActivityRuntime : ComponentActivity() {
         // Restore the saved rumble master toggle into the native gate (NativeApp.onPadRumble).
         NativeApp.sRumbleEnabled = ControllerMappings.rumbleEnabled()
         NativeApp.sPhoneRumbleEnabled = ControllerMappings.phoneRumbleEnabled()
+        // Starts the temperature poll if the overlay wants it. Costs one file read every couple
+        // of seconds and stops entirely when the option is off.
+        runCatching { com.armsx2.Thermals.load(this) }
         // Push the saved haptic strength + achievement-sound volume into their native gates before
         // any rumble or unlock sound can fire (both default to 1.0 = as authored until set here).
         ControllerMappings.syncHapticIntensity()

android/armsx3-ui/app/src/main/java/com/armsx2/ui/settings/OverlayTab.kt

@@ -244,6 +244,31 @@ fun OverlayTab(state: MutableState<Settings>) {
             ffToasts.value = it
             com.armsx2.runtime.MainActivityRuntime.prefs.edit { putBoolean("ui.hotkeyToasts", it) }
         }
+        SettingsDivider()
+        // Device temperatures on the perf overlay. Android exposes no supported API for SoC
+        // temperatures, so these come from the thermal sysfs, whose zone naming and units are
+        // vendor-specific -- a device with no readable zone simply shows nothing here.
+        val ctx = androidx.compose.ui.platform.LocalContext.current
+        ToggleRow(
+            str("overlay.toggle.temps"),
+            com.armsx2.Thermals.osdEnabled.value,
+            description = str("overlay.toggle.temps.description"),
+        ) {
+            com.armsx2.Thermals.setOsdEnabled(ctx, it)
+        }
+        // Poll interval. Asked for explicitly as the mitigation for sensor overhead. No
+        // "realtime" option: a temperature that moves slower than a second is not worth the
+        // syscalls.
+        if (com.armsx2.Thermals.osdEnabled.value) {
+            IntSliderRow(
+                label = str("overlay.tempInterval.label"),
+                value = com.armsx2.Thermals.intervalSec.value,
+                min = 1,
+                max = 5,
+                valueFormatter = { "${it}s" },
+                onChange = { com.armsx2.Thermals.setIntervalSec(it) },
+            )
+        }
     }
 }