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/nrf5340-net-pac/src/ctrlap_ns/approtect/disable.rs

@@ -0,0 +1,80 @@
+#[doc = "Register `DISABLE` reader"]
+pub struct R(crate::R<DISABLE_SPEC>);
+impl core::ops::Deref for R {
+    type Target = crate::R<DISABLE_SPEC>;
+    #[inline(always)]
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+impl From<crate::R<DISABLE_SPEC>> for R {
+    #[inline(always)]
+    fn from(reader: crate::R<DISABLE_SPEC>) -> Self {
+        R(reader)
+    }
+}
+#[doc = "Register `DISABLE` writer"]
+pub struct W(crate::W<DISABLE_SPEC>);
+impl core::ops::Deref for W {
+    type Target = crate::W<DISABLE_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<DISABLE_SPEC>> for W {
+    #[inline(always)]
+    fn from(writer: crate::W<DISABLE_SPEC>) -> Self {
+        W(writer)
+    }
+}
+#[doc = "Field `KEY` reader - If the value of the KEY field is non-zero, and the KEY fields match on both the CPU and debugger sides, disable APPROTECT and enable debug access to non-secure mode until the next pin reset, brown-out reset, power-on reset, or watchog timer reset. After reset the debugger side register has a fixed KEY value. To enable debug access, both CTRL-AP and UICR.APPROTECT protection needs to be disabled."]
+pub type KEY_R = crate::FieldReader<u32, u32>;
+#[doc = "Field `KEY` writer - If the value of the KEY field is non-zero, and the KEY fields match on both the CPU and debugger sides, disable APPROTECT and enable debug access to non-secure mode until the next pin reset, brown-out reset, power-on reset, or watchog timer reset. After reset the debugger side register has a fixed KEY value. To enable debug access, both CTRL-AP and UICR.APPROTECT protection needs to be disabled."]
+pub type KEY_W<'a, const O: u8> = crate::FieldWriter<'a, u32, DISABLE_SPEC, u32, u32, 32, O>;
+impl R {
+    #[doc = "Bits 0:31 - If the value of the KEY field is non-zero, and the KEY fields match on both the CPU and debugger sides, disable APPROTECT and enable debug access to non-secure mode until the next pin reset, brown-out reset, power-on reset, or watchog timer reset. After reset the debugger side register has a fixed KEY value. To enable debug access, both CTRL-AP and UICR.APPROTECT protection needs to be disabled."]
+    #[inline(always)]
+    pub fn key(&self) -> KEY_R {
+        KEY_R::new(self.bits)
+    }
+}
+impl W {
+    #[doc = "Bits 0:31 - If the value of the KEY field is non-zero, and the KEY fields match on both the CPU and debugger sides, disable APPROTECT and enable debug access to non-secure mode until the next pin reset, brown-out reset, power-on reset, or watchog timer reset. After reset the debugger side register has a fixed KEY value. To enable debug access, both CTRL-AP and UICR.APPROTECT protection needs to be disabled."]
+    #[inline(always)]
+    pub fn key(&mut self) -> KEY_W<0> {
+        KEY_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 = "This register disables the APPROTECT register and enables debug access to non-secure 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 [disable](index.html) module"]
+pub struct DISABLE_SPEC;
+impl crate::RegisterSpec for DISABLE_SPEC {
+    type Ux = u32;
+}
+#[doc = "`read()` method returns [disable::R](R) reader structure"]
+impl crate::Readable for DISABLE_SPEC {
+    type Reader = R;
+}
+#[doc = "`write(|w| ..)` method takes [disable::W](W) writer structure"]
+impl crate::Writable for DISABLE_SPEC {
+    type Writer = W;
+}
+#[doc = "`reset()` method sets DISABLE to value 0"]
+impl crate::Resettable for DISABLE_SPEC {
+    #[inline(always)]
+    fn reset_value() -> Self::Ux {
+        0
+    }
+}

vendor/nrf5340-net-pac/src/ctrlap_ns/approtect/lock.rs

@@ -0,0 +1,126 @@
+#[doc = "Register `LOCK` reader"]
+pub struct R(crate::R<LOCK_SPEC>);
+impl core::ops::Deref for R {
+    type Target = crate::R<LOCK_SPEC>;
+    #[inline(always)]
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+impl From<crate::R<LOCK_SPEC>> for R {
+    #[inline(always)]
+    fn from(reader: crate::R<LOCK_SPEC>) -> Self {
+        R(reader)
+    }
+}
+#[doc = "Register `LOCK` writer"]
+pub struct W(crate::W<LOCK_SPEC>);
+impl core::ops::Deref for W {
+    type Target = crate::W<LOCK_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<LOCK_SPEC>> for W {
+    #[inline(always)]
+    fn from(writer: crate::W<LOCK_SPEC>) -> Self {
+        W(writer)
+    }
+}
+#[doc = "Field `LOCK` reader - Lock the APPROTECT.DISABLE register from being written to until next reset"]
+pub type LOCK_R = crate::BitReader<LOCK_A>;
+#[doc = "Lock the APPROTECT.DISABLE register from being written to until next reset\n\nValue on reset: 0"]
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub enum LOCK_A {
+    #[doc = "0: Register APPROTECT.DISABLE is writeable"]
+    UNLOCKED = 0,
+    #[doc = "1: Register APPROTECT.DISABLE is read-only"]
+    LOCKED = 1,
+}
+impl From<LOCK_A> for bool {
+    #[inline(always)]
+    fn from(variant: LOCK_A) -> Self {
+        variant as u8 != 0
+    }
+}
+impl LOCK_R {
+    #[doc = "Get enumerated values variant"]
+    #[inline(always)]
+    pub fn variant(&self) -> LOCK_A {
+        match self.bits {
+            false => LOCK_A::UNLOCKED,
+            true => LOCK_A::LOCKED,
+        }
+    }
+    #[doc = "Checks if the value of the field is `UNLOCKED`"]
+    #[inline(always)]
+    pub fn is_unlocked(&self) -> bool {
+        *self == LOCK_A::UNLOCKED
+    }
+    #[doc = "Checks if the value of the field is `LOCKED`"]
+    #[inline(always)]
+    pub fn is_locked(&self) -> bool {
+        *self == LOCK_A::LOCKED
+    }
+}
+#[doc = "Field `LOCK` writer - Lock the APPROTECT.DISABLE register from being written to until next reset"]
+pub type LOCK_W<'a, const O: u8> = crate::BitWriter<'a, u32, LOCK_SPEC, LOCK_A, O>;
+impl<'a, const O: u8> LOCK_W<'a, O> {
+    #[doc = "Register APPROTECT.DISABLE is writeable"]
+    #[inline(always)]
+    pub fn unlocked(self) -> &'a mut W {
+        self.variant(LOCK_A::UNLOCKED)
+    }
+    #[doc = "Register APPROTECT.DISABLE is read-only"]
+    #[inline(always)]
+    pub fn locked(self) -> &'a mut W {
+        self.variant(LOCK_A::LOCKED)
+    }
+}
+impl R {
+    #[doc = "Bit 0 - Lock the APPROTECT.DISABLE register from being written to until next reset"]
+    #[inline(always)]
+    pub fn lock(&self) -> LOCK_R {
+        LOCK_R::new((self.bits & 1) != 0)
+    }
+}
+impl W {
+    #[doc = "Bit 0 - Lock the APPROTECT.DISABLE register from being written to until next reset"]
+    #[inline(always)]
+    pub fn lock(&mut self) -> LOCK_W<0> {
+        LOCK_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 = "This register locks the APPROTECT.DISABLE register from being written to until next reset.\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 [lock](index.html) module"]
+pub struct LOCK_SPEC;
+impl crate::RegisterSpec for LOCK_SPEC {
+    type Ux = u32;
+}
+#[doc = "`read()` method returns [lock::R](R) reader structure"]
+impl crate::Readable for LOCK_SPEC {
+    type Reader = R;
+}
+#[doc = "`write(|w| ..)` method takes [lock::W](W) writer structure"]
+impl crate::Writable for LOCK_SPEC {
+    type Writer = W;
+}
+#[doc = "`reset()` method sets LOCK to value 0"]
+impl crate::Resettable for LOCK_SPEC {
+    #[inline(always)]
+    fn reset_value() -> Self::Ux {
+        0
+    }
+}