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/radio/crccnf.rs

@@ -0,0 +1,214 @@
+#[doc = "Register `CRCCNF` reader"]
+pub struct R(crate::R<CRCCNF_SPEC>);
+impl core::ops::Deref for R {
+    type Target = crate::R<CRCCNF_SPEC>;
+    #[inline(always)]
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+impl From<crate::R<CRCCNF_SPEC>> for R {
+    #[inline(always)]
+    fn from(reader: crate::R<CRCCNF_SPEC>) -> Self {
+        R(reader)
+    }
+}
+#[doc = "Register `CRCCNF` writer"]
+pub struct W(crate::W<CRCCNF_SPEC>);
+impl core::ops::Deref for W {
+    type Target = crate::W<CRCCNF_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<CRCCNF_SPEC>> for W {
+    #[inline(always)]
+    fn from(writer: crate::W<CRCCNF_SPEC>) -> Self {
+        W(writer)
+    }
+}
+#[doc = "Field `LEN` reader - CRC length. Decision point: START task."]
+pub type LEN_R = crate::FieldReader<u8, LEN_A>;
+#[doc = "CRC length. Decision point: START task.\n\nValue on reset: 0"]
+#[derive(Clone, Copy, Debug, PartialEq)]
+#[repr(u8)]
+pub enum LEN_A {
+    #[doc = "0: CRC calculation disabled."]
+    DISABLED = 0,
+    #[doc = "1: One byte long CRC."]
+    ONE = 1,
+    #[doc = "2: Two bytes long CRC."]
+    TWO = 2,
+    #[doc = "3: Three bytes long CRC."]
+    THREE = 3,
+}
+impl From<LEN_A> for u8 {
+    #[inline(always)]
+    fn from(variant: LEN_A) -> Self {
+        variant as _
+    }
+}
+impl LEN_R {
+    #[doc = "Get enumerated values variant"]
+    #[inline(always)]
+    pub fn variant(&self) -> LEN_A {
+        match self.bits {
+            0 => LEN_A::DISABLED,
+            1 => LEN_A::ONE,
+            2 => LEN_A::TWO,
+            3 => LEN_A::THREE,
+            _ => unreachable!(),
+        }
+    }
+    #[doc = "Checks if the value of the field is `DISABLED`"]
+    #[inline(always)]
+    pub fn is_disabled(&self) -> bool {
+        *self == LEN_A::DISABLED
+    }
+    #[doc = "Checks if the value of the field is `ONE`"]
+    #[inline(always)]
+    pub fn is_one(&self) -> bool {
+        *self == LEN_A::ONE
+    }
+    #[doc = "Checks if the value of the field is `TWO`"]
+    #[inline(always)]
+    pub fn is_two(&self) -> bool {
+        *self == LEN_A::TWO
+    }
+    #[doc = "Checks if the value of the field is `THREE`"]
+    #[inline(always)]
+    pub fn is_three(&self) -> bool {
+        *self == LEN_A::THREE
+    }
+}
+#[doc = "Field `LEN` writer - CRC length. Decision point: START task."]
+pub type LEN_W<'a, const O: u8> = crate::FieldWriterSafe<'a, u32, CRCCNF_SPEC, u8, LEN_A, 2, O>;
+impl<'a, const O: u8> LEN_W<'a, O> {
+    #[doc = "CRC calculation disabled."]
+    #[inline(always)]
+    pub fn disabled(self) -> &'a mut W {
+        self.variant(LEN_A::DISABLED)
+    }
+    #[doc = "One byte long CRC."]
+    #[inline(always)]
+    pub fn one(self) -> &'a mut W {
+        self.variant(LEN_A::ONE)
+    }
+    #[doc = "Two bytes long CRC."]
+    #[inline(always)]
+    pub fn two(self) -> &'a mut W {
+        self.variant(LEN_A::TWO)
+    }
+    #[doc = "Three bytes long CRC."]
+    #[inline(always)]
+    pub fn three(self) -> &'a mut W {
+        self.variant(LEN_A::THREE)
+    }
+}
+#[doc = "Field `SKIPADDR` reader - Leave packet address field out of the CRC calculation. Decision point: START task."]
+pub type SKIPADDR_R = crate::BitReader<SKIPADDR_A>;
+#[doc = "Leave packet address field out of the CRC calculation. Decision point: START task.\n\nValue on reset: 0"]
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub enum SKIPADDR_A {
+    #[doc = "0: Include packet address in CRC calculation."]
+    INCLUDE = 0,
+    #[doc = "1: Packet address is skipped in CRC calculation. The CRC calculation will start at the first byte after the address."]
+    SKIP = 1,
+}
+impl From<SKIPADDR_A> for bool {
+    #[inline(always)]
+    fn from(variant: SKIPADDR_A) -> Self {
+        variant as u8 != 0
+    }
+}
+impl SKIPADDR_R {
+    #[doc = "Get enumerated values variant"]
+    #[inline(always)]
+    pub fn variant(&self) -> SKIPADDR_A {
+        match self.bits {
+            false => SKIPADDR_A::INCLUDE,
+            true => SKIPADDR_A::SKIP,
+        }
+    }
+    #[doc = "Checks if the value of the field is `INCLUDE`"]
+    #[inline(always)]
+    pub fn is_include(&self) -> bool {
+        *self == SKIPADDR_A::INCLUDE
+    }
+    #[doc = "Checks if the value of the field is `SKIP`"]
+    #[inline(always)]
+    pub fn is_skip(&self) -> bool {
+        *self == SKIPADDR_A::SKIP
+    }
+}
+#[doc = "Field `SKIPADDR` writer - Leave packet address field out of the CRC calculation. Decision point: START task."]
+pub type SKIPADDR_W<'a, const O: u8> = crate::BitWriter<'a, u32, CRCCNF_SPEC, SKIPADDR_A, O>;
+impl<'a, const O: u8> SKIPADDR_W<'a, O> {
+    #[doc = "Include packet address in CRC calculation."]
+    #[inline(always)]
+    pub fn include(self) -> &'a mut W {
+        self.variant(SKIPADDR_A::INCLUDE)
+    }
+    #[doc = "Packet address is skipped in CRC calculation. The CRC calculation will start at the first byte after the address."]
+    #[inline(always)]
+    pub fn skip(self) -> &'a mut W {
+        self.variant(SKIPADDR_A::SKIP)
+    }
+}
+impl R {
+    #[doc = "Bits 0:1 - CRC length. Decision point: START task."]
+    #[inline(always)]
+    pub fn len(&self) -> LEN_R {
+        LEN_R::new((self.bits & 3) as u8)
+    }
+    #[doc = "Bit 8 - Leave packet address field out of the CRC calculation. Decision point: START task."]
+    #[inline(always)]
+    pub fn skipaddr(&self) -> SKIPADDR_R {
+        SKIPADDR_R::new(((self.bits >> 8) & 1) != 0)
+    }
+}
+impl W {
+    #[doc = "Bits 0:1 - CRC length. Decision point: START task."]
+    #[inline(always)]
+    pub fn len(&mut self) -> LEN_W<0> {
+        LEN_W::new(self)
+    }
+    #[doc = "Bit 8 - Leave packet address field out of the CRC calculation. Decision point: START task."]
+    #[inline(always)]
+    pub fn skipaddr(&mut self) -> SKIPADDR_W<8> {
+        SKIPADDR_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 = "CRC configuration.\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 [crccnf](index.html) module"]
+pub struct CRCCNF_SPEC;
+impl crate::RegisterSpec for CRCCNF_SPEC {
+    type Ux = u32;
+}
+#[doc = "`read()` method returns [crccnf::R](R) reader structure"]
+impl crate::Readable for CRCCNF_SPEC {
+    type Reader = R;
+}
+#[doc = "`write(|w| ..)` method takes [crccnf::W](W) writer structure"]
+impl crate::Writable for CRCCNF_SPEC {
+    type Writer = W;
+}
+#[doc = "`reset()` method sets CRCCNF to value 0"]
+impl crate::Resettable for CRCCNF_SPEC {
+    #[inline(always)]
+    fn reset_value() -> Self::Ux {
+        0
+    }
+}