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/proc-macro-error/tests/ui/abort.rs

@@ -0,0 +1,11 @@
+extern crate test_crate;
+use test_crate::*;
+
+abort_from!(one, two);
+abort_to_string!(one, two);
+abort_format!(one, two);
+direct_abort!(one, two);
+abort_notes!(one, two);
+abort_call_site_test!(one, two);
+
+fn main() {}

vendor/proc-macro-error/tests/ui/abort.stderr

@@ -0,0 +1,48 @@
+error: abort!(span, from) test
+ --> $DIR/abort.rs:4:13
+  |
+4 | abort_from!(one, two);
+  |             ^^^
+
+error: abort!(span, single_expr) test
+ --> $DIR/abort.rs:5:18
+  |
+5 | abort_to_string!(one, two);
+  |                  ^^^
+
+error: abort!(span, expr1, expr2) test
+ --> $DIR/abort.rs:6:15
+  |
+6 | abort_format!(one, two);
+  |               ^^^
+
+error: Diagnostic::abort() test
+ --> $DIR/abort.rs:7:15
+  |
+7 | direct_abort!(one, two);
+  |               ^^^
+
+error: This is an error
+
+  = note: simple note
+  = help: simple help
+  = help: simple hint
+  = note: simple yay
+  = note: format note
+  = note: Some note
+  = note: spanned simple note
+  = note: spanned format note
+  = note: Some note
+
+ --> $DIR/abort.rs:8:14
+  |
+8 | abort_notes!(one, two);
+  |              ^^^
+
+error: abort_call_site! test
+ --> $DIR/abort.rs:9:1
+  |
+9 | abort_call_site_test!(one, two);
+  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+  |
+  = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)

vendor/proc-macro-error/tests/ui/append_dummy.rs

@@ -0,0 +1,13 @@
+extern crate test_crate;
+use test_crate::*;
+
+enum NeedDefault {
+    A,
+    B
+}
+
+append_dummy!(need_default);
+
+fn main() {
+    let _ = NeedDefault::default();
+}

vendor/proc-macro-error/tests/ui/append_dummy.stderr

@@ -0,0 +1,5 @@
+error: append_dummy test
+ --> $DIR/append_dummy.rs:9:15
+  |
+9 | append_dummy!(need_default);
+  |               ^^^^^^^^^^^^

vendor/proc-macro-error/tests/ui/children_messages.rs

@@ -0,0 +1,6 @@
+extern crate test_crate;
+use test_crate::*;
+
+children_messages!(one, two, three, four);
+
+fn main() {}

vendor/proc-macro-error/tests/ui/children_messages.stderr

@@ -0,0 +1,23 @@
+error: main macro message
+ --> $DIR/children_messages.rs:4:20
+  |
+4 | children_messages!(one, two, three, four);
+  |                    ^^^
+
+error: child message
+ --> $DIR/children_messages.rs:4:25
+  |
+4 | children_messages!(one, two, three, four);
+  |                         ^^^
+
+error: main syn::Error
+ --> $DIR/children_messages.rs:4:30
+  |
+4 | children_messages!(one, two, three, four);
+  |                              ^^^^^
+
+error: child syn::Error
+ --> $DIR/children_messages.rs:4:37
+  |
+4 | children_messages!(one, two, three, four);
+  |                                     ^^^^

vendor/proc-macro-error/tests/ui/dummy.rs

@@ -0,0 +1,13 @@
+extern crate test_crate;
+use test_crate::*;
+
+enum NeedDefault {
+    A,
+    B
+}
+
+dummy!(need_default);
+
+fn main() {
+    let _ = NeedDefault::default();
+}

vendor/proc-macro-error/tests/ui/dummy.stderr

@@ -0,0 +1,5 @@
+error: set_dummy test
+ --> $DIR/dummy.rs:9:8
+  |
+9 | dummy!(need_default);
+  |        ^^^^^^^^^^^^

vendor/proc-macro-error/tests/ui/emit.rs

@@ -0,0 +1,7 @@
+extern crate test_crate;
+use test_crate::*;
+
+emit!(one, two, three, four, five);
+emit_notes!(one, two);
+
+fn main() {}

vendor/proc-macro-error/tests/ui/emit.stderr

@@ -0,0 +1,48 @@
+error: emit!(span, from) test
+ --> $DIR/emit.rs:4:7
+  |
+4 | emit!(one, two, three, four, five);
+  |       ^^^
+
+error: emit!(span, expr1, expr2) test
+ --> $DIR/emit.rs:4:12
+  |
+4 | emit!(one, two, three, four, five);
+  |            ^^^
+
+error: emit!(span, single_expr) test
+ --> $DIR/emit.rs:4:17
+  |
+4 | emit!(one, two, three, four, five);
+  |                 ^^^^^
+
+error: Diagnostic::emit() test
+ --> $DIR/emit.rs:4:24
+  |
+4 | emit!(one, two, three, four, five);
+  |                        ^^^^
+
+error: emit_call_site_error!(expr) test
+ --> $DIR/emit.rs:4:1
+  |
+4 | emit!(one, two, three, four, five);
+  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+  |
+  = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: This is an error
+
+  = note: simple note
+  = help: simple help
+  = help: simple hint
+  = note: simple yay
+  = note: format note
+  = note: Some note
+  = note: spanned simple note
+  = note: spanned format note
+  = note: Some note
+
+ --> $DIR/emit.rs:5:13
+  |
+5 | emit_notes!(one, two);
+  |             ^^^

vendor/proc-macro-error/tests/ui/explicit_span_range.rs

@@ -0,0 +1,6 @@
+extern crate test_crate;
+use test_crate::*;
+
+explicit_span_range!(one, two, three, four);
+
+fn main() {}

vendor/proc-macro-error/tests/ui/explicit_span_range.stderr

@@ -0,0 +1,5 @@
+error: explicit SpanRange
+ --> $DIR/explicit_span_range.rs:4:22
+  |
+4 | explicit_span_range!(one, two, three, four);
+  |                      ^^^^^^^^^^^^^^^

vendor/proc-macro-error/tests/ui/misuse.rs

@@ -0,0 +1,11 @@
+extern crate proc_macro_error;
+use proc_macro_error::abort;
+
+struct Foo;
+
+#[allow(unused)]
+fn foo() {
+    abort!(Foo, "BOOM");
+}
+
+fn main() {}

vendor/proc-macro-error/tests/ui/misuse.stderr

@@ -0,0 +1,13 @@
+error[E0599]: no method named `FIRST_ARG_MUST_EITHER_BE_Span_OR_IMPLEMENT_ToTokens_OR_BE_SpanRange` found for reference `&Foo` in the current scope
+ --> $DIR/misuse.rs:8:5
+  |
+4 | struct Foo;
+  | ----------- doesn't satisfy `Foo: quote::to_tokens::ToTokens`
+...
+8 |     abort!(Foo, "BOOM");
+  |     ^^^^^^^^^^^^^^^^^^^^ method not found in `&Foo`
+  |
+  = note: the method `FIRST_ARG_MUST_EITHER_BE_Span_OR_IMPLEMENT_ToTokens_OR_BE_SpanRange` exists but the following trait bounds were not satisfied:
+          `Foo: quote::to_tokens::ToTokens`
+          which is required by `&Foo: proc_macro_error::__export::ToTokensAsSpanRange`
+  = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)

vendor/proc-macro-error/tests/ui/multiple_tokens.rs

@@ -0,0 +1,6 @@
+extern crate test_crate;
+
+#[test_crate::multiple_tokens]
+type T = ();
+
+fn main() {}

vendor/proc-macro-error/tests/ui/multiple_tokens.stderr

@@ -0,0 +1,5 @@
+error: ...
+ --> $DIR/multiple_tokens.rs:4:1
+  |
+4 | type T = ();
+  | ^^^^^^^^^^^^

vendor/proc-macro-error/tests/ui/not_proc_macro.rs

@@ -0,0 +1,4 @@
+use proc_macro_error::proc_macro_error;
+
+#[proc_macro_error]
+fn main() {}

vendor/proc-macro-error/tests/ui/not_proc_macro.stderr

@@ -0,0 +1,10 @@
+error: #[proc_macro_error] attribute can be used only with procedural macros
+
+  = hint: if you are really sure that #[proc_macro_error] should be applied to this exact function, use #[proc_macro_error(allow_not_macro)]
+
+ --> $DIR/not_proc_macro.rs:3:1
+  |
+3 | #[proc_macro_error]
+  | ^^^^^^^^^^^^^^^^^^^
+  |
+  = note: this error originates in an attribute macro (in Nightly builds, run with -Z macro-backtrace for more info)

vendor/proc-macro-error/tests/ui/option_ext.rs

@@ -0,0 +1,6 @@
+extern crate test_crate;
+use test_crate::*;
+
+option_ext!(one, two);
+
+fn main() {}

vendor/proc-macro-error/tests/ui/option_ext.stderr

@@ -0,0 +1,7 @@
+error: Option::expect_or_abort() test
+ --> $DIR/option_ext.rs:4:1
+  |
+4 | option_ext!(one, two);
+  | ^^^^^^^^^^^^^^^^^^^^^^
+  |
+  = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)

vendor/proc-macro-error/tests/ui/proc_macro_hack.rs

@@ -0,0 +1,10 @@
+// Adapted from https://github.com/dtolnay/proc-macro-hack/blob/master/example/src/main.rs
+// Licensed under either of Apache License, Version 2.0 or MIT license at your option.
+
+use proc_macro_hack_test::add_one;
+
+fn main() {
+    let two = 2;
+    let nine = add_one!(two) + add_one!(2 + 3);
+    println!("nine = {}", nine);
+}

vendor/proc-macro-error/tests/ui/proc_macro_hack.stderr

@@ -0,0 +1,26 @@
+error: BOOM
+ --> $DIR/proc_macro_hack.rs:8:25
+  |
+8 |     let nine = add_one!(two) + add_one!(2 + 3);
+  |                         ^^^
+  |
+  = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: BOOM
+ --> $DIR/proc_macro_hack.rs:8:41
+  |
+8 |     let nine = add_one!(two) + add_one!(2 + 3);
+  |                                         ^^^^^
+  |
+  = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+warning: unreachable expression
+ --> $DIR/proc_macro_hack.rs:8:32
+  |
+8 |     let nine = add_one!(two) + add_one!(2 + 3);
+  |                -------------   ^^^^^^^^^^^^^^^ unreachable expression
+  |                |
+  |                any code following this expression is unreachable
+  |
+  = note: `#[warn(unreachable_code)]` on by default
+  = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)

vendor/proc-macro-error/tests/ui/result_ext.rs

@@ -0,0 +1,7 @@
+extern crate test_crate;
+use test_crate::*;
+
+result_unwrap_or_abort!(one, two);
+result_expect_or_abort!(one, two);
+
+fn main() {}

vendor/proc-macro-error/tests/ui/result_ext.stderr

@@ -0,0 +1,11 @@
+error: Result::unwrap_or_abort() test
+ --> $DIR/result_ext.rs:4:25
+  |
+4 | result_unwrap_or_abort!(one, two);
+  |                         ^^^
+
+error: BOOM: Result::expect_or_abort() test
+ --> $DIR/result_ext.rs:5:25
+  |
+5 | result_expect_or_abort!(one, two);
+  |                         ^^^

vendor/proc-macro-error/tests/ui/to_tokens_span.rs

@@ -0,0 +1,6 @@
+extern crate test_crate;
+use test_crate::*;
+
+to_tokens_span!(std::option::Option);
+
+fn main() {}

vendor/proc-macro-error/tests/ui/to_tokens_span.stderr

@@ -0,0 +1,11 @@
+error: whole type
+ --> $DIR/to_tokens_span.rs:4:17
+  |
+4 | to_tokens_span!(std::option::Option);
+  |                 ^^^^^^^^^^^^^^^^^^^
+
+error: explicit .span()
+ --> $DIR/to_tokens_span.rs:4:17
+  |
+4 | to_tokens_span!(std::option::Option);
+  |                 ^^^

vendor/proc-macro-error/tests/ui/unknown_setting.rs

@@ -0,0 +1,4 @@
+use proc_macro_error::proc_macro_error;
+
+#[proc_macro_error(allow_not_macro, assert_unwind_safe, trololo)]
+fn main() {}

vendor/proc-macro-error/tests/ui/unknown_setting.stderr

@@ -0,0 +1,5 @@
+error: unknown setting `trololo`, expected one of `assert_unwind_safe`, `allow_not_macro`, `proc_macro_hack`
+ --> $DIR/unknown_setting.rs:3:57
+  |
+3 | #[proc_macro_error(allow_not_macro, assert_unwind_safe, trololo)]
+  |                                                         ^^^^^^^

vendor/proc-macro-error/tests/ui/unrelated_panic.rs

@@ -0,0 +1,6 @@
+extern crate test_crate;
+use test_crate::*;
+
+unrelated_panic!();
+
+fn main() {}

vendor/proc-macro-error/tests/ui/unrelated_panic.stderr

@@ -0,0 +1,7 @@
+error: proc macro panicked
+ --> $DIR/unrelated_panic.rs:4:1
+  |
+4 | unrelated_panic!();
+  | ^^^^^^^^^^^^^^^^^^^
+  |
+  = help: message: unrelated panic test