feat: add display UI with splash screen, dashboard, and RSSI sparkline

Implement full SSD1306 OLED display support:
- Splash screen on boot (1.5s) with project name, version, board
- Dashboard showing radio state, config, counters, RSSI/SNR
- RSSI history sparkline (64-sample ring buffer, 2px-wide bars)
- DisplayOn/DisplayOff host commands routed via dedicated channel
- Pure render functions against generic DrawTarget (no hardware coupling)
- Display on/off control bypasses radio task entirely

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

vendor/esp-hal/src/reset.rs

@@ -0,0 +1,112 @@
+//! # Hardware and Software Reset
+//!
+//! ## Overview
+//! Espressif chips provide four types of reset that occur at different levels,
+//! namely CPU Reset, Core Reset, System Reset, and Chip Reset. All reset types
+//! mentioned above (except Chip Reset) preserve the data stored in internal
+//! memory.
+//!
+//! The Hardware and Software Reset module provides functions for
+//! performing hardware and software resets and includes functions for
+//! retrieving the reset reason and the wakeup cause after a reset.
+//!
+//! The module defines a set of sleep sources (`SleepSource`) that indicate the
+//! source of the wakeup event. It also includes a set of flags (`WakeupReason`)
+//! that represent different wakeup sources and enable/disable wakeup triggers
+//! for specific events.
+
+use crate::rtc_cntl::SocResetReason;
+
+/// Source of the wakeup event
+#[derive(Debug, Copy, Clone)]
+pub enum SleepSource {
+    /// In case of deep sleep, reset was not caused by exit from deep sleep
+    Undefined = 0,
+    /// Not a wakeup cause, used to disable all wakeup sources with
+    /// esp_sleep_disable_wakeup_source
+    All,
+    /// Wakeup caused by external signal using RTC_IO
+    Ext0,
+    /// Wakeup caused by external signal using RTC_CNTL
+    Ext1,
+    /// Wakeup caused by timer
+    Timer,
+    /// Wakeup caused by touchpad
+    TouchPad,
+    /// Wakeup caused by ULP program
+    Ulp,
+    /// Wakeup caused by GPIO (light sleep only on ESP32, S2 and S3)
+    Gpio,
+    /// Wakeup caused by UART (light sleep only)
+    Uart,
+    /// Wakeup caused by WIFI (light sleep only)
+    Wifi,
+    /// Wakeup caused by COCPU int
+    Cocpu,
+    /// Wakeup caused by COCPU crash
+    CocpuTrapTrig,
+    /// Wakeup caused by BT (light sleep only)
+    BT,
+}
+
+bitflags::bitflags! {
+    #[allow(unused)]
+    pub(crate) struct WakeupReason: u32 {
+        const NoSleep         = 0;
+        #[cfg(pm_support_ext0_wakeup)]
+        /// EXT0 GPIO wakeup
+        const ExtEvent0Trig   = 1 << 0;
+        #[cfg(pm_support_ext1_wakeup)]
+        /// EXT1 GPIO wakeup
+        const ExtEvent1Trig   = 1 << 1;
+        /// GPIO wakeup (light sleep only)
+        const GpioTrigEn      = 1 << 2;
+        #[cfg(not(any(esp32c6, esp32h2)))]
+        /// Timer wakeup
+        const TimerTrigEn     = 1 << 3;
+        #[cfg(any(esp32c6, esp32h2))]
+        /// Timer wakeup
+        const TimerTrigEn     = 1 << 4;
+        #[cfg(pm_support_wifi_wakeup)]
+        /// MAC wakeup (light sleep only)
+        const WifiTrigEn      = 1 << 5;
+        /// UART0 wakeup (light sleep only)
+        const Uart0TrigEn     = 1 << 6;
+        /// UART1 wakeup (light sleep only)
+        const Uart1TrigEn     = 1 << 7;
+        #[cfg(pm_support_touch_sensor_wakeup)]
+        /// Touch wakeup
+        const TouchTrigEn     = 1 << 8;
+        #[cfg(ulp_supported)]
+        /// ULP wakeup
+        const UlpTrigEn       = 1 << 9;
+        #[cfg(pm_support_bt_wakeup)]
+        /// BT wakeup (light sleep only)
+        const BtTrigEn        = 1 << 10;
+        #[cfg(riscv_coproc_supported)]
+        const CocpuTrigEn     = 1 << 11;
+        #[cfg(riscv_coproc_supported)]
+        const CocpuTrapTrigEn = 1 << 13;
+    }
+}
+
+/// Performs a software reset on the chip.
+pub fn software_reset() {
+    crate::rom::software_reset();
+}
+
+/// Performs a software reset on the CPU.
+pub fn software_reset_cpu() {
+    crate::rom::software_reset_cpu();
+}
+
+/// Retrieves the reason for the last reset as a SocResetReason enum value.
+/// Returns `None` if the reset reason cannot be determined.
+pub fn reset_reason() -> Option<SocResetReason> {
+    crate::rtc_cntl::reset_reason(crate::Cpu::current())
+}
+
+/// Retrieves the cause of the last wakeup event as a SleepSource enum value.
+pub fn wakeup_cause() -> SleepSource {
+    crate::rtc_cntl::wakeup_cause()
+}