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/nrf52840-pac/src/power/ramstatus.rs

@@ -0,0 +1,197 @@
+#[doc = "Register `RAMSTATUS` reader"]
+pub struct R(crate::R<RAMSTATUS_SPEC>);
+impl core::ops::Deref for R {
+    type Target = crate::R<RAMSTATUS_SPEC>;
+    #[inline(always)]
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+impl From<crate::R<RAMSTATUS_SPEC>> for R {
+    #[inline(always)]
+    fn from(reader: crate::R<RAMSTATUS_SPEC>) -> Self {
+        R(reader)
+    }
+}
+#[doc = "Field `RAMBLOCK0` reader - RAM block 0 is on or off/powering up"]
+pub type RAMBLOCK0_R = crate::BitReader<RAMBLOCK0_A>;
+#[doc = "RAM block 0 is on or off/powering up\n\nValue on reset: 0"]
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub enum RAMBLOCK0_A {
+    #[doc = "0: Off"]
+    OFF = 0,
+    #[doc = "1: On"]
+    ON = 1,
+}
+impl From<RAMBLOCK0_A> for bool {
+    #[inline(always)]
+    fn from(variant: RAMBLOCK0_A) -> Self {
+        variant as u8 != 0
+    }
+}
+impl RAMBLOCK0_R {
+    #[doc = "Get enumerated values variant"]
+    #[inline(always)]
+    pub fn variant(&self) -> RAMBLOCK0_A {
+        match self.bits {
+            false => RAMBLOCK0_A::OFF,
+            true => RAMBLOCK0_A::ON,
+        }
+    }
+    #[doc = "Checks if the value of the field is `OFF`"]
+    #[inline(always)]
+    pub fn is_off(&self) -> bool {
+        *self == RAMBLOCK0_A::OFF
+    }
+    #[doc = "Checks if the value of the field is `ON`"]
+    #[inline(always)]
+    pub fn is_on(&self) -> bool {
+        *self == RAMBLOCK0_A::ON
+    }
+}
+#[doc = "Field `RAMBLOCK1` reader - RAM block 1 is on or off/powering up"]
+pub type RAMBLOCK1_R = crate::BitReader<RAMBLOCK1_A>;
+#[doc = "RAM block 1 is on or off/powering up\n\nValue on reset: 0"]
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub enum RAMBLOCK1_A {
+    #[doc = "0: Off"]
+    OFF = 0,
+    #[doc = "1: On"]
+    ON = 1,
+}
+impl From<RAMBLOCK1_A> for bool {
+    #[inline(always)]
+    fn from(variant: RAMBLOCK1_A) -> Self {
+        variant as u8 != 0
+    }
+}
+impl RAMBLOCK1_R {
+    #[doc = "Get enumerated values variant"]
+    #[inline(always)]
+    pub fn variant(&self) -> RAMBLOCK1_A {
+        match self.bits {
+            false => RAMBLOCK1_A::OFF,
+            true => RAMBLOCK1_A::ON,
+        }
+    }
+    #[doc = "Checks if the value of the field is `OFF`"]
+    #[inline(always)]
+    pub fn is_off(&self) -> bool {
+        *self == RAMBLOCK1_A::OFF
+    }
+    #[doc = "Checks if the value of the field is `ON`"]
+    #[inline(always)]
+    pub fn is_on(&self) -> bool {
+        *self == RAMBLOCK1_A::ON
+    }
+}
+#[doc = "Field `RAMBLOCK2` reader - RAM block 2 is on or off/powering up"]
+pub type RAMBLOCK2_R = crate::BitReader<RAMBLOCK2_A>;
+#[doc = "RAM block 2 is on or off/powering up\n\nValue on reset: 0"]
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub enum RAMBLOCK2_A {
+    #[doc = "0: Off"]
+    OFF = 0,
+    #[doc = "1: On"]
+    ON = 1,
+}
+impl From<RAMBLOCK2_A> for bool {
+    #[inline(always)]
+    fn from(variant: RAMBLOCK2_A) -> Self {
+        variant as u8 != 0
+    }
+}
+impl RAMBLOCK2_R {
+    #[doc = "Get enumerated values variant"]
+    #[inline(always)]
+    pub fn variant(&self) -> RAMBLOCK2_A {
+        match self.bits {
+            false => RAMBLOCK2_A::OFF,
+            true => RAMBLOCK2_A::ON,
+        }
+    }
+    #[doc = "Checks if the value of the field is `OFF`"]
+    #[inline(always)]
+    pub fn is_off(&self) -> bool {
+        *self == RAMBLOCK2_A::OFF
+    }
+    #[doc = "Checks if the value of the field is `ON`"]
+    #[inline(always)]
+    pub fn is_on(&self) -> bool {
+        *self == RAMBLOCK2_A::ON
+    }
+}
+#[doc = "Field `RAMBLOCK3` reader - RAM block 3 is on or off/powering up"]
+pub type RAMBLOCK3_R = crate::BitReader<RAMBLOCK3_A>;
+#[doc = "RAM block 3 is on or off/powering up\n\nValue on reset: 0"]
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub enum RAMBLOCK3_A {
+    #[doc = "0: Off"]
+    OFF = 0,
+    #[doc = "1: On"]
+    ON = 1,
+}
+impl From<RAMBLOCK3_A> for bool {
+    #[inline(always)]
+    fn from(variant: RAMBLOCK3_A) -> Self {
+        variant as u8 != 0
+    }
+}
+impl RAMBLOCK3_R {
+    #[doc = "Get enumerated values variant"]
+    #[inline(always)]
+    pub fn variant(&self) -> RAMBLOCK3_A {
+        match self.bits {
+            false => RAMBLOCK3_A::OFF,
+            true => RAMBLOCK3_A::ON,
+        }
+    }
+    #[doc = "Checks if the value of the field is `OFF`"]
+    #[inline(always)]
+    pub fn is_off(&self) -> bool {
+        *self == RAMBLOCK3_A::OFF
+    }
+    #[doc = "Checks if the value of the field is `ON`"]
+    #[inline(always)]
+    pub fn is_on(&self) -> bool {
+        *self == RAMBLOCK3_A::ON
+    }
+}
+impl R {
+    #[doc = "Bit 0 - RAM block 0 is on or off/powering up"]
+    #[inline(always)]
+    pub fn ramblock0(&self) -> RAMBLOCK0_R {
+        RAMBLOCK0_R::new((self.bits & 1) != 0)
+    }
+    #[doc = "Bit 1 - RAM block 1 is on or off/powering up"]
+    #[inline(always)]
+    pub fn ramblock1(&self) -> RAMBLOCK1_R {
+        RAMBLOCK1_R::new(((self.bits >> 1) & 1) != 0)
+    }
+    #[doc = "Bit 2 - RAM block 2 is on or off/powering up"]
+    #[inline(always)]
+    pub fn ramblock2(&self) -> RAMBLOCK2_R {
+        RAMBLOCK2_R::new(((self.bits >> 2) & 1) != 0)
+    }
+    #[doc = "Bit 3 - RAM block 3 is on or off/powering up"]
+    #[inline(always)]
+    pub fn ramblock3(&self) -> RAMBLOCK3_R {
+        RAMBLOCK3_R::new(((self.bits >> 3) & 1) != 0)
+    }
+}
+#[doc = "Deprecated register - RAM status register\n\nThis register you can [`read`](crate::generic::Reg::read). See [API](https://docs.rs/svd2rust/#read--modify--write-api).\n\nFor information about available fields see [ramstatus](index.html) module"]
+pub struct RAMSTATUS_SPEC;
+impl crate::RegisterSpec for RAMSTATUS_SPEC {
+    type Ux = u32;
+}
+#[doc = "`read()` method returns [ramstatus::R](R) reader structure"]
+impl crate::Readable for RAMSTATUS_SPEC {
+    type Reader = R;
+}
+#[doc = "`reset()` method sets RAMSTATUS to value 0"]
+impl crate::Resettable for RAMSTATUS_SPEC {
+    #[inline(always)]
+    fn reset_value() -> Self::Ux {
+        0
+    }
+}