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/nrf52811-pac/src/pdm/sample/maxcnt.rs

@@ -0,0 +1,80 @@
+#[doc = "Register `MAXCNT` reader"]
+pub struct R(crate::R<MAXCNT_SPEC>);
+impl core::ops::Deref for R {
+    type Target = crate::R<MAXCNT_SPEC>;
+    #[inline(always)]
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+impl From<crate::R<MAXCNT_SPEC>> for R {
+    #[inline(always)]
+    fn from(reader: crate::R<MAXCNT_SPEC>) -> Self {
+        R(reader)
+    }
+}
+#[doc = "Register `MAXCNT` writer"]
+pub struct W(crate::W<MAXCNT_SPEC>);
+impl core::ops::Deref for W {
+    type Target = crate::W<MAXCNT_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<MAXCNT_SPEC>> for W {
+    #[inline(always)]
+    fn from(writer: crate::W<MAXCNT_SPEC>) -> Self {
+        W(writer)
+    }
+}
+#[doc = "Field `BUFFSIZE` reader - Length of DMA RAM allocation in number of samples"]
+pub type BUFFSIZE_R = crate::FieldReader<u16, u16>;
+#[doc = "Field `BUFFSIZE` writer - Length of DMA RAM allocation in number of samples"]
+pub type BUFFSIZE_W<'a, const O: u8> = crate::FieldWriter<'a, u32, MAXCNT_SPEC, u16, u16, 15, O>;
+impl R {
+    #[doc = "Bits 0:14 - Length of DMA RAM allocation in number of samples"]
+    #[inline(always)]
+    pub fn buffsize(&self) -> BUFFSIZE_R {
+        BUFFSIZE_R::new((self.bits & 0x7fff) as u16)
+    }
+}
+impl W {
+    #[doc = "Bits 0:14 - Length of DMA RAM allocation in number of samples"]
+    #[inline(always)]
+    pub fn buffsize(&mut self) -> BUFFSIZE_W<0> {
+        BUFFSIZE_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 = "Number of samples to allocate memory for in EasyDMA mode\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 [maxcnt](index.html) module"]
+pub struct MAXCNT_SPEC;
+impl crate::RegisterSpec for MAXCNT_SPEC {
+    type Ux = u32;
+}
+#[doc = "`read()` method returns [maxcnt::R](R) reader structure"]
+impl crate::Readable for MAXCNT_SPEC {
+    type Reader = R;
+}
+#[doc = "`write(|w| ..)` method takes [maxcnt::W](W) writer structure"]
+impl crate::Writable for MAXCNT_SPEC {
+    type Writer = W;
+}
+#[doc = "`reset()` method sets MAXCNT to value 0"]
+impl crate::Resettable for MAXCNT_SPEC {
+    #[inline(always)]
+    fn reset_value() -> Self::Ux {
+        0
+    }
+}

vendor/nrf52811-pac/src/pdm/sample/ptr.rs

@@ -0,0 +1,80 @@
+#[doc = "Register `PTR` reader"]
+pub struct R(crate::R<PTR_SPEC>);
+impl core::ops::Deref for R {
+    type Target = crate::R<PTR_SPEC>;
+    #[inline(always)]
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+impl From<crate::R<PTR_SPEC>> for R {
+    #[inline(always)]
+    fn from(reader: crate::R<PTR_SPEC>) -> Self {
+        R(reader)
+    }
+}
+#[doc = "Register `PTR` writer"]
+pub struct W(crate::W<PTR_SPEC>);
+impl core::ops::Deref for W {
+    type Target = crate::W<PTR_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<PTR_SPEC>> for W {
+    #[inline(always)]
+    fn from(writer: crate::W<PTR_SPEC>) -> Self {
+        W(writer)
+    }
+}
+#[doc = "Field `SAMPLEPTR` reader - Address to write PDM samples to over DMA"]
+pub type SAMPLEPTR_R = crate::FieldReader<u32, u32>;
+#[doc = "Field `SAMPLEPTR` writer - Address to write PDM samples to over DMA"]
+pub type SAMPLEPTR_W<'a, const O: u8> = crate::FieldWriter<'a, u32, PTR_SPEC, u32, u32, 32, O>;
+impl R {
+    #[doc = "Bits 0:31 - Address to write PDM samples to over DMA"]
+    #[inline(always)]
+    pub fn sampleptr(&self) -> SAMPLEPTR_R {
+        SAMPLEPTR_R::new(self.bits)
+    }
+}
+impl W {
+    #[doc = "Bits 0:31 - Address to write PDM samples to over DMA"]
+    #[inline(always)]
+    pub fn sampleptr(&mut self) -> SAMPLEPTR_W<0> {
+        SAMPLEPTR_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 = "RAM address pointer to write samples to with EasyDMA\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 [ptr](index.html) module"]
+pub struct PTR_SPEC;
+impl crate::RegisterSpec for PTR_SPEC {
+    type Ux = u32;
+}
+#[doc = "`read()` method returns [ptr::R](R) reader structure"]
+impl crate::Readable for PTR_SPEC {
+    type Reader = R;
+}
+#[doc = "`write(|w| ..)` method takes [ptr::W](W) writer structure"]
+impl crate::Writable for PTR_SPEC {
+    type Writer = W;
+}
+#[doc = "`reset()` method sets PTR to value 0"]
+impl crate::Resettable for PTR_SPEC {
+    #[inline(always)]
+    fn reset_value() -> Self::Ux {
+        0
+    }
+}