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/ecb.rs

@@ -0,0 +1,49 @@
+#[doc = r"Register block"]
+#[repr(C)]
+pub struct RegisterBlock {
+    #[doc = "0x00 - Start ECB block encrypt"]
+    pub tasks_startecb: TASKS_STARTECB,
+    #[doc = "0x04 - Abort a possible executing ECB operation"]
+    pub tasks_stopecb: TASKS_STOPECB,
+    _reserved2: [u8; 0xf8],
+    #[doc = "0x100 - ECB block encrypt complete"]
+    pub events_endecb: EVENTS_ENDECB,
+    #[doc = "0x104 - ECB block encrypt aborted because of a STOPECB task or due to an error"]
+    pub events_errorecb: EVENTS_ERRORECB,
+    _reserved4: [u8; 0x01fc],
+    #[doc = "0x304 - Enable interrupt"]
+    pub intenset: INTENSET,
+    #[doc = "0x308 - Disable interrupt"]
+    pub intenclr: INTENCLR,
+    _reserved6: [u8; 0x01f8],
+    #[doc = "0x504 - ECB block encrypt memory pointers"]
+    pub ecbdataptr: ECBDATAPTR,
+}
+#[doc = "TASKS_STARTECB (w) register accessor: an alias for `Reg<TASKS_STARTECB_SPEC>`"]
+pub type TASKS_STARTECB = crate::Reg<tasks_startecb::TASKS_STARTECB_SPEC>;
+#[doc = "Start ECB block encrypt"]
+pub mod tasks_startecb;
+#[doc = "TASKS_STOPECB (w) register accessor: an alias for `Reg<TASKS_STOPECB_SPEC>`"]
+pub type TASKS_STOPECB = crate::Reg<tasks_stopecb::TASKS_STOPECB_SPEC>;
+#[doc = "Abort a possible executing ECB operation"]
+pub mod tasks_stopecb;
+#[doc = "EVENTS_ENDECB (rw) register accessor: an alias for `Reg<EVENTS_ENDECB_SPEC>`"]
+pub type EVENTS_ENDECB = crate::Reg<events_endecb::EVENTS_ENDECB_SPEC>;
+#[doc = "ECB block encrypt complete"]
+pub mod events_endecb;
+#[doc = "EVENTS_ERRORECB (rw) register accessor: an alias for `Reg<EVENTS_ERRORECB_SPEC>`"]
+pub type EVENTS_ERRORECB = crate::Reg<events_errorecb::EVENTS_ERRORECB_SPEC>;
+#[doc = "ECB block encrypt aborted because of a STOPECB task or due to an error"]
+pub mod events_errorecb;
+#[doc = "INTENSET (rw) register accessor: an alias for `Reg<INTENSET_SPEC>`"]
+pub type INTENSET = crate::Reg<intenset::INTENSET_SPEC>;
+#[doc = "Enable interrupt"]
+pub mod intenset;
+#[doc = "INTENCLR (rw) register accessor: an alias for `Reg<INTENCLR_SPEC>`"]
+pub type INTENCLR = crate::Reg<intenclr::INTENCLR_SPEC>;
+#[doc = "Disable interrupt"]
+pub mod intenclr;
+#[doc = "ECBDATAPTR (rw) register accessor: an alias for `Reg<ECBDATAPTR_SPEC>`"]
+pub type ECBDATAPTR = crate::Reg<ecbdataptr::ECBDATAPTR_SPEC>;
+#[doc = "ECB block encrypt memory pointers"]
+pub mod ecbdataptr;