Remove dead functions and unused Montserrat font flags

Six public API functions had no callers anywhere in the firmware:
splash_prev, splash_set_active, splash_current_name, splash_count,
ble_is_connected, imu_set_rotation, power_is_usb_connected,
power_usb_changed. Trimming them lets power.cpp drop the VBUS state
machine (cached_usb, usb_changed_flag, last_vbus_ms,
enableVbusVoltageMeasure). usage_rate_reset becomes file-static since
the only caller is in usage_rate.cpp itself. Montserrat font flags in
platformio.ini were enabled but never referenced.

firmware/src/ble.cpp

@@ -232,8 +232,3 @@ void ble_keyboard_release(void) {
     input_kbd->setValue(report, sizeof(report));
     input_kbd->notify();
 }
-
-bool ble_is_connected(void) {
-    return state == BLE_STATE_CONNECTED;
-}
-

firmware/src/ble.h

@@ -23,5 +23,3 @@ void ble_request_refresh(void);
 // BLE HID keyboard
 void ble_keyboard_press(uint8_t key, uint8_t modifier);
 void ble_keyboard_release(void);
-bool ble_is_connected(void);
-

firmware/src/imu.cpp

@@ -74,8 +74,3 @@ void imu_tick(void) {
 uint8_t imu_get_rotation(void) {
     return current_rotation;
 }
-
-void imu_set_rotation(uint8_t r) {
-    current_rotation = r % 4;
-    Serial.printf("Rotation: %d (manual)\n", current_rotation);
-}

firmware/src/power.cpp

@@ -4,15 +4,13 @@
 
 // Poll intervals
 #define BATTERY_POLL_MS   2000
-#define VBUS_POLL_MS      500
+#define CHARGING_POLL_MS  500
 
 static int      cached_pct      = -1;
 static bool     cached_charging = false;
-static bool     cached_usb      = false;
-static bool     usb_changed_flag = false;
 static bool     pwr_pressed_flag = false;
 static uint32_t last_battery_ms  = 0;
-static uint32_t last_vbus_ms     = 0;
+static uint32_t last_charging_ms = 0;
 static uint32_t last_pwr_ms      = 0;
 #define PWR_POLL_MS 50
 
@@ -23,9 +21,7 @@ void power_init(void) {
     }
     Serial.println("AXP2101 init OK");
 
-    // Enable battery and VBUS ADC measurements
     pmu.enableBattDetection();
-    pmu.enableVbusVoltageMeasure();
     pmu.enableBattVoltageMeasure();
 
     // Enable PWR button short-press IRQ (mid button for cycling screens)
@@ -33,8 +29,6 @@ void power_init(void) {
     pmu.clearIrqStatus();
     pmu.enableIRQ(XPOWERS_AXP2101_PKEY_SHORT_IRQ);
 
-    // Read initial state
-    cached_usb = pmu.isVbusIn();
     cached_charging = pmu.isCharging();
     cached_pct = pmu.getBatteryPercent();
 }
@@ -42,18 +36,11 @@ void power_init(void) {
 void power_tick(void) {
     uint32_t now = millis();
 
-    // Poll VBUS status
-    if (now - last_vbus_ms >= VBUS_POLL_MS) {
-        last_vbus_ms = now;
-        bool usb_now = pmu.isVbusIn();
-        if (usb_now != cached_usb) {
-            cached_usb = usb_now;
-            usb_changed_flag = true;
-        }
+    if (now - last_charging_ms >= CHARGING_POLL_MS) {
+        last_charging_ms = now;
         cached_charging = pmu.isCharging();
     }
 
-    // Poll battery level
     if (now - last_battery_ms >= BATTERY_POLL_MS) {
         last_battery_ms = now;
         cached_pct = pmu.getBatteryPercent();
@@ -78,18 +65,6 @@ bool power_is_charging(void) {
     return cached_charging;
 }
 
-bool power_is_usb_connected(void) {
-    return cached_usb;
-}
-
-bool power_usb_changed(void) {
-    if (usb_changed_flag) {
-        usb_changed_flag = false;
-        return true;
-    }
-    return false;
-}
-
 bool power_pwr_pressed(void) {
     if (pwr_pressed_flag) {
         pwr_pressed_flag = false;

firmware/src/power.h

@@ -4,6 +4,4 @@ void power_init(void);
 void power_tick(void);
 int  power_battery_pct(void);    // 0-100, or -1 if no battery
 bool power_is_charging(void);
-bool power_is_usb_connected(void);
-bool power_usb_changed(void);    // true once per VBUS state transition
 bool power_pwr_pressed(void);    // true once per AXP2101 PWR button short-press

firmware/src/splash.cpp

@@ -166,19 +166,6 @@ void splash_next(void) {
     Serial.printf("splash: -> %s\n", a->name);
 }
 
-void splash_prev(void) {
-    if (SPLASH_ANIM_COUNT == 0) return;
-    cur_anim = (cur_anim + SPLASH_ANIM_COUNT - 1) % SPLASH_ANIM_COUNT;
-    cur_frame = 0;
-    frame_started_ms = millis();
-    last_pick_ms = frame_started_ms;
-    const splash_anim_def_t *a = &splash_anims[cur_anim];
-    render_frame(a->frames[0], a->palette);
-    Serial.printf("splash: <- %s\n", a->name);
-}
-
-void splash_set_active(bool a) { active = a; }
-
 void splash_pick_for_current_rate(void) {
     if (SPLASH_ANIM_COUNT == 0) return;
     int g = usage_rate_group();
@@ -214,10 +201,3 @@ void splash_hide(void) {
 lv_obj_t* splash_get_root(void) {
     return splash_container;
 }
-
-const char *splash_current_name(void) {
-    if (SPLASH_ANIM_COUNT == 0) return "(none)";
-    return splash_anims[cur_anim].name;
-}
-
-uint16_t splash_count(void) { return SPLASH_ANIM_COUNT; }

firmware/src/splash.h

@@ -12,12 +12,6 @@ void splash_tick(void);
 // Cycle to the next animation in the catalog.
 void splash_next(void);
 
-// Cycle to the previous animation in the catalog.
-void splash_prev(void);
-
-// Pause/resume rendering (e.g. when a different screen is active).
-void splash_set_active(bool active);
-
 // Show/hide the splash container.
 void splash_show(void);
 void splash_hide(void);
@@ -32,8 +26,3 @@ bool splash_is_active(void);
 
 // Root container (so ui.cpp can attach a click event).
 lv_obj_t* splash_get_root(void);
-
-// Current animation name (for debug/UI).
-const char *splash_current_name(void);
-
-uint16_t splash_count(void);

firmware/src/usage_rate.cpp

@@ -33,7 +33,7 @@ static inline uint8_t oldest_idx(void) {
     return (head + RING_SIZE - count) % RING_SIZE;
 }
 
-void usage_rate_reset(void) {
+static void usage_rate_reset(void) {
     count = 0;
     head  = 0;
 }

firmware/src/usage_rate.h

@@ -10,6 +10,3 @@ void usage_rate_sample(float session_pct);
 // 0 = idle, 1 = normal, 2 = active, 3 = heavy.
 // Defaults to 0 when the buffer doesn't have enough samples yet.
 int usage_rate_group(void);
-
-// Clear the buffer (e.g. when the 5-hour session window resets).
-void usage_rate_reset(void);