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/zerocopy-derive/tests/ui/late_compile_pass.rs

@@ -0,0 +1,108 @@
+// Copyright 2019 The Fuchsia Authors
+//
+// Licensed under a BSD-style license <LICENSE-BSD>, Apache License, Version 2.0
+// <LICENSE-APACHE or https://www.apache.org/licenses/LICENSE-2.0>, or the MIT
+// license <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your option.
+// This file may not be copied, modified, or distributed except according to
+// those terms.
+
+#[macro_use]
+extern crate zerocopy_renamed;
+
+#[path = "../include.rs"]
+mod util;
+
+use zerocopy_renamed::KnownLayout;
+
+use self::util::util::{NotZerocopy, AU16};
+
+fn main() {}
+
+// These tests cause errors which are generated by a later compilation pass than
+// the other errors we generate, and so if they're compiled in the same file,
+// the compiler will never get to that pass, and so we won't get the errors.
+
+//
+// TryFromBytes errors
+//
+
+#[derive(TryFromBytes)]
+//~[msrv]^ ERROR: the trait bound `NotZerocopy: zerocopy_renamed::TryFromBytes` is not satisfied
+//~[stable, nightly]^^ ERROR: the trait bound `NotZerocopy: zerocopy_renamed::TryFromBytes` is not satisfied
+#[zerocopy(crate = "zerocopy_renamed")]
+struct TryFromBytes1 {
+    value: NotZerocopy,
+}
+
+//
+// FromZeros errors
+//
+
+#[derive(FromZeros)]
+//~[msrv]^ ERROR: the trait bound `NotZerocopy: zerocopy_renamed::TryFromBytes` is not satisfied
+//~[msrv, stable, nightly]^^ ERROR: the trait bound `NotZerocopy: FromZeros` is not satisfied
+//~[stable, nightly]^^^ ERROR: the trait bound `NotZerocopy: zerocopy_renamed::TryFromBytes` is not satisfied
+#[zerocopy(crate = "zerocopy_renamed")]
+struct FromZeros1 {
+    value: NotZerocopy,
+}
+
+//
+// FromBytes errors
+//
+
+#[derive(FromBytes)]
+//~[msrv]^ ERROR: the trait bound `NotZerocopy: zerocopy_renamed::TryFromBytes` is not satisfied
+//~[msrv, stable, nightly]^^ ERROR: the trait bound `NotZerocopy: FromZeros` is not satisfied
+//~[msrv]^^^ ERROR: the trait bound `NotZerocopy: zerocopy_renamed::FromBytes` is not satisfied
+//~[stable, nightly]^^^^ ERROR: the trait bound `NotZerocopy: zerocopy_renamed::TryFromBytes` is not satisfied
+//~[stable, nightly]^^^^^ ERROR: the trait bound `NotZerocopy: zerocopy_renamed::FromBytes` is not satisfied
+//~[stable, nightly]^^^^^^ ERROR: the trait bound `NotZerocopy: zerocopy_renamed::FromBytes` is not satisfied
+#[zerocopy(crate = "zerocopy_renamed")]
+struct FromBytes1 {
+    value: NotZerocopy,
+}
+
+//
+// IntoBytes errors
+//
+
+#[derive(IntoBytes)]
+//~[msrv]^ ERROR: the trait bound `NotZerocopy: zerocopy_renamed::IntoBytes` is not satisfied
+//~[stable, nightly]^^ ERROR: the trait bound `NotZerocopy: zerocopy_renamed::IntoBytes` is not satisfied
+#[zerocopy(crate = "zerocopy_renamed")]
+#[repr(C)]
+struct IntoBytes1 {
+    value: NotZerocopy,
+}
+
+//
+// Unaligned errors
+//
+
+#[derive(Unaligned)]
+//~[msrv, stable, nightly]^ ERROR: the trait bound `AU16: zerocopy_renamed::Unaligned` is not satisfied
+#[zerocopy(crate = "zerocopy_renamed")]
+#[repr(C)]
+struct Unaligned1 {
+    aligned: AU16,
+}
+
+// This specifically tests a bug we had in an old version of the code in which
+// the trait bound would only be enforced for the first field's type.
+#[derive(Unaligned)]
+//~[msrv, stable, nightly]^ ERROR: the trait bound `AU16: zerocopy_renamed::Unaligned` is not satisfied
+#[zerocopy(crate = "zerocopy_renamed")]
+#[repr(C)]
+struct Unaligned2 {
+    unaligned: u8,
+    aligned: AU16,
+}
+
+#[derive(Unaligned)]
+//~[msrv, stable, nightly]^ ERROR: the trait bound `AU16: zerocopy_renamed::Unaligned` is not satisfied
+#[zerocopy(crate = "zerocopy_renamed")]
+#[repr(transparent)]
+struct Unaligned3 {
+    aligned: AU16,
+}