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-app-pac/src/ipc_ns.rs

@@ -0,0 +1,77 @@
+#[doc = r"Register block"]
+#[repr(C)]
+pub struct RegisterBlock {
+    #[doc = "0x00..0x40 - Description collection: Trigger events on IPC channel enabled in SEND_CNF\\[n\\]"]
+    pub tasks_send: [TASKS_SEND; 16],
+    _reserved1: [u8; 0x40],
+    #[doc = "0x80..0xc0 - Description collection: Subscribe configuration for task SEND\\[n\\]"]
+    pub subscribe_send: [SUBSCRIBE_SEND; 16],
+    _reserved2: [u8; 0x40],
+    #[doc = "0x100..0x140 - Description collection: Event received on one or more of the enabled IPC channels in RECEIVE_CNF\\[n\\]"]
+    pub events_receive: [EVENTS_RECEIVE; 16],
+    _reserved3: [u8; 0x40],
+    #[doc = "0x180..0x1c0 - Description collection: Publish configuration for event RECEIVE\\[n\\]"]
+    pub publish_receive: [PUBLISH_RECEIVE; 16],
+    _reserved4: [u8; 0x0140],
+    #[doc = "0x300 - Enable or disable interrupt"]
+    pub inten: INTEN,
+    #[doc = "0x304 - Enable interrupt"]
+    pub intenset: INTENSET,
+    #[doc = "0x308 - Disable interrupt"]
+    pub intenclr: INTENCLR,
+    #[doc = "0x30c - Pending interrupts"]
+    pub intpend: INTPEND,
+    _reserved8: [u8; 0x0200],
+    #[doc = "0x510..0x550 - Description collection: Send event configuration for TASKS_SEND\\[n\\]"]
+    pub send_cnf: [SEND_CNF; 16],
+    _reserved9: [u8; 0x40],
+    #[doc = "0x590..0x5d0 - Description collection: Receive event configuration for EVENTS_RECEIVE\\[n\\]"]
+    pub receive_cnf: [RECEIVE_CNF; 16],
+    _reserved10: [u8; 0x40],
+    #[doc = "0x610..0x618 - Description collection: General purpose memory"]
+    pub gpmem: [GPMEM; 2],
+}
+#[doc = "TASKS_SEND (w) register accessor: an alias for `Reg<TASKS_SEND_SPEC>`"]
+pub type TASKS_SEND = crate::Reg<tasks_send::TASKS_SEND_SPEC>;
+#[doc = "Description collection: Trigger events on IPC channel enabled in SEND_CNF\\[n\\]"]
+pub mod tasks_send;
+#[doc = "SUBSCRIBE_SEND (rw) register accessor: an alias for `Reg<SUBSCRIBE_SEND_SPEC>`"]
+pub type SUBSCRIBE_SEND = crate::Reg<subscribe_send::SUBSCRIBE_SEND_SPEC>;
+#[doc = "Description collection: Subscribe configuration for task SEND\\[n\\]"]
+pub mod subscribe_send;
+#[doc = "EVENTS_RECEIVE (rw) register accessor: an alias for `Reg<EVENTS_RECEIVE_SPEC>`"]
+pub type EVENTS_RECEIVE = crate::Reg<events_receive::EVENTS_RECEIVE_SPEC>;
+#[doc = "Description collection: Event received on one or more of the enabled IPC channels in RECEIVE_CNF\\[n\\]"]
+pub mod events_receive;
+#[doc = "PUBLISH_RECEIVE (rw) register accessor: an alias for `Reg<PUBLISH_RECEIVE_SPEC>`"]
+pub type PUBLISH_RECEIVE = crate::Reg<publish_receive::PUBLISH_RECEIVE_SPEC>;
+#[doc = "Description collection: Publish configuration for event RECEIVE\\[n\\]"]
+pub mod publish_receive;
+#[doc = "INTEN (rw) register accessor: an alias for `Reg<INTEN_SPEC>`"]
+pub type INTEN = crate::Reg<inten::INTEN_SPEC>;
+#[doc = "Enable or disable interrupt"]
+pub mod inten;
+#[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 = "INTPEND (r) register accessor: an alias for `Reg<INTPEND_SPEC>`"]
+pub type INTPEND = crate::Reg<intpend::INTPEND_SPEC>;
+#[doc = "Pending interrupts"]
+pub mod intpend;
+#[doc = "SEND_CNF (rw) register accessor: an alias for `Reg<SEND_CNF_SPEC>`"]
+pub type SEND_CNF = crate::Reg<send_cnf::SEND_CNF_SPEC>;
+#[doc = "Description collection: Send event configuration for TASKS_SEND\\[n\\]"]
+pub mod send_cnf;
+#[doc = "RECEIVE_CNF (rw) register accessor: an alias for `Reg<RECEIVE_CNF_SPEC>`"]
+pub type RECEIVE_CNF = crate::Reg<receive_cnf::RECEIVE_CNF_SPEC>;
+#[doc = "Description collection: Receive event configuration for EVENTS_RECEIVE\\[n\\]"]
+pub mod receive_cnf;
+#[doc = "GPMEM (rw) register accessor: an alias for `Reg<GPMEM_SPEC>`"]
+pub type GPMEM = crate::Reg<gpmem::GPMEM_SPEC>;
+#[doc = "Description collection: General purpose memory"]
+pub mod gpmem;