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/nrf51-pac/src/timer0/bitmode.rs

@@ -0,0 +1,155 @@
+#[doc = "Register `BITMODE` reader"]
+pub struct R(crate::R<BITMODE_SPEC>);
+impl core::ops::Deref for R {
+    type Target = crate::R<BITMODE_SPEC>;
+    #[inline(always)]
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+impl From<crate::R<BITMODE_SPEC>> for R {
+    #[inline(always)]
+    fn from(reader: crate::R<BITMODE_SPEC>) -> Self {
+        R(reader)
+    }
+}
+#[doc = "Register `BITMODE` writer"]
+pub struct W(crate::W<BITMODE_SPEC>);
+impl core::ops::Deref for W {
+    type Target = crate::W<BITMODE_SPEC>;
+    #[inline(always)]
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+impl core::ops::DerefMut for W {
+    #[inline(always)]
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.0
+    }
+}
+impl From<crate::W<BITMODE_SPEC>> for W {
+    #[inline(always)]
+    fn from(writer: crate::W<BITMODE_SPEC>) -> Self {
+        W(writer)
+    }
+}
+#[doc = "Field `BITMODE` reader - Sets timer behaviour ro be like the implementation of a timer with width as indicated."]
+pub type BITMODE_R = crate::FieldReader<u8, BITMODE_A>;
+#[doc = "Sets timer behaviour ro be like the implementation of a timer with width as indicated.\n\nValue on reset: 0"]
+#[derive(Clone, Copy, Debug, PartialEq)]
+#[repr(u8)]
+pub enum BITMODE_A {
+    #[doc = "0: 16-bit timer behaviour."]
+    _16BIT = 0,
+    #[doc = "1: 8-bit timer behaviour."]
+    _08BIT = 1,
+    #[doc = "2: 24-bit timer behaviour."]
+    _24BIT = 2,
+    #[doc = "3: 32-bit timer behaviour."]
+    _32BIT = 3,
+}
+impl From<BITMODE_A> for u8 {
+    #[inline(always)]
+    fn from(variant: BITMODE_A) -> Self {
+        variant as _
+    }
+}
+impl BITMODE_R {
+    #[doc = "Get enumerated values variant"]
+    #[inline(always)]
+    pub fn variant(&self) -> BITMODE_A {
+        match self.bits {
+            0 => BITMODE_A::_16BIT,
+            1 => BITMODE_A::_08BIT,
+            2 => BITMODE_A::_24BIT,
+            3 => BITMODE_A::_32BIT,
+            _ => unreachable!(),
+        }
+    }
+    #[doc = "Checks if the value of the field is `_16BIT`"]
+    #[inline(always)]
+    pub fn is_16bit(&self) -> bool {
+        *self == BITMODE_A::_16BIT
+    }
+    #[doc = "Checks if the value of the field is `_08BIT`"]
+    #[inline(always)]
+    pub fn is_08bit(&self) -> bool {
+        *self == BITMODE_A::_08BIT
+    }
+    #[doc = "Checks if the value of the field is `_24BIT`"]
+    #[inline(always)]
+    pub fn is_24bit(&self) -> bool {
+        *self == BITMODE_A::_24BIT
+    }
+    #[doc = "Checks if the value of the field is `_32BIT`"]
+    #[inline(always)]
+    pub fn is_32bit(&self) -> bool {
+        *self == BITMODE_A::_32BIT
+    }
+}
+#[doc = "Field `BITMODE` writer - Sets timer behaviour ro be like the implementation of a timer with width as indicated."]
+pub type BITMODE_W<'a, const O: u8> =
+    crate::FieldWriterSafe<'a, u32, BITMODE_SPEC, u8, BITMODE_A, 2, O>;
+impl<'a, const O: u8> BITMODE_W<'a, O> {
+    #[doc = "16-bit timer behaviour."]
+    #[inline(always)]
+    pub fn _16bit(self) -> &'a mut W {
+        self.variant(BITMODE_A::_16BIT)
+    }
+    #[doc = "8-bit timer behaviour."]
+    #[inline(always)]
+    pub fn _08bit(self) -> &'a mut W {
+        self.variant(BITMODE_A::_08BIT)
+    }
+    #[doc = "24-bit timer behaviour."]
+    #[inline(always)]
+    pub fn _24bit(self) -> &'a mut W {
+        self.variant(BITMODE_A::_24BIT)
+    }
+    #[doc = "32-bit timer behaviour."]
+    #[inline(always)]
+    pub fn _32bit(self) -> &'a mut W {
+        self.variant(BITMODE_A::_32BIT)
+    }
+}
+impl R {
+    #[doc = "Bits 0:1 - Sets timer behaviour ro be like the implementation of a timer with width as indicated."]
+    #[inline(always)]
+    pub fn bitmode(&self) -> BITMODE_R {
+        BITMODE_R::new((self.bits & 3) as u8)
+    }
+}
+impl W {
+    #[doc = "Bits 0:1 - Sets timer behaviour ro be like the implementation of a timer with width as indicated."]
+    #[inline(always)]
+    pub fn bitmode(&mut self) -> BITMODE_W<0> {
+        BITMODE_W::new(self)
+    }
+    #[doc = "Writes raw bits to the register."]
+    #[inline(always)]
+    pub unsafe fn bits(&mut self, bits: u32) -> &mut Self {
+        self.0.bits(bits);
+        self
+    }
+}
+#[doc = "Sets timer behaviour.\n\nThis register you can [`read`](crate::generic::Reg::read), [`write_with_zero`](crate::generic::Reg::write_with_zero), [`reset`](crate::generic::Reg::reset), [`write`](crate::generic::Reg::write), [`modify`](crate::generic::Reg::modify). See [API](https://docs.rs/svd2rust/#read--modify--write-api).\n\nFor information about available fields see [bitmode](index.html) module"]
+pub struct BITMODE_SPEC;
+impl crate::RegisterSpec for BITMODE_SPEC {
+    type Ux = u32;
+}
+#[doc = "`read()` method returns [bitmode::R](R) reader structure"]
+impl crate::Readable for BITMODE_SPEC {
+    type Reader = R;
+}
+#[doc = "`write(|w| ..)` method takes [bitmode::W](W) writer structure"]
+impl crate::Writable for BITMODE_SPEC {
+    type Writer = W;
+}
+#[doc = "`reset()` method sets BITMODE to value 0"]
+impl crate::Resettable for BITMODE_SPEC {
+    #[inline(always)]
+    fn reset_value() -> Self::Ux {
+        0
+    }
+}