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-error2/tests/ui/abort.rs

@@ -0,0 +1,10 @@
+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-error2/tests/ui/abort.stderr

@@ -0,0 +1,48 @@
+error: abort!(span, from) test
+ --> tests/ui/abort.rs:3:13
+  |
+3 | abort_from!(one, two);
+  |             ^^^
+
+error: abort!(span, single_expr) test
+ --> tests/ui/abort.rs:4:18
+  |
+4 | abort_to_string!(one, two);
+  |                  ^^^
+
+error: abort!(span, expr1, expr2) test
+ --> tests/ui/abort.rs:5:15
+  |
+5 | abort_format!(one, two);
+  |               ^^^
+
+error: Diagnostic::abort() test
+ --> tests/ui/abort.rs:6:15
+  |
+6 | 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
+
+ --> tests/ui/abort.rs:7:14
+  |
+7 | abort_notes!(one, two);
+  |              ^^^
+
+error: abort_call_site! test
+ --> tests/ui/abort.rs:8:1
+  |
+8 | abort_call_site_test!(one, two);
+  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+  |
+  = note: this error originates in the macro `abort_call_site_test` (in Nightly builds, run with -Z macro-backtrace for more info)

vendor/proc-macro-error2/tests/ui/append_dummy.rs

@@ -0,0 +1,12 @@
+use test_crate::*;
+
+enum NeedDefault {
+    A,
+    B,
+}
+
+append_dummy!(need_default);
+
+fn main() {
+    let _ = NeedDefault::default();
+}

vendor/proc-macro-error2/tests/ui/append_dummy.stderr

@@ -0,0 +1,5 @@
+error: append_dummy test
+ --> tests/ui/append_dummy.rs:8:15
+  |
+8 | append_dummy!(need_default);
+  |               ^^^^^^^^^^^^

vendor/proc-macro-error2/tests/ui/children_messages.rs

@@ -0,0 +1,5 @@
+use test_crate::*;
+
+children_messages!(one, two, three, four);
+
+fn main() {}

vendor/proc-macro-error2/tests/ui/children_messages.stderr

@@ -0,0 +1,23 @@
+error: main macro message
+ --> tests/ui/children_messages.rs:3:20
+  |
+3 | children_messages!(one, two, three, four);
+  |                    ^^^
+
+error: child message
+ --> tests/ui/children_messages.rs:3:25
+  |
+3 | children_messages!(one, two, three, four);
+  |                         ^^^
+
+error: main syn::Error
+ --> tests/ui/children_messages.rs:3:30
+  |
+3 | children_messages!(one, two, three, four);
+  |                              ^^^^^
+
+error: child syn::Error
+ --> tests/ui/children_messages.rs:3:37
+  |
+3 | children_messages!(one, two, three, four);
+  |                                     ^^^^

vendor/proc-macro-error2/tests/ui/dummy.rs

@@ -0,0 +1,12 @@
+use test_crate::*;
+
+enum NeedDefault {
+    A,
+    B,
+}
+
+dummy!(need_default);
+
+fn main() {
+    let _ = NeedDefault::default();
+}

vendor/proc-macro-error2/tests/ui/dummy.stderr

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

vendor/proc-macro-error2/tests/ui/emit.rs

@@ -0,0 +1,6 @@
+use test_crate::*;
+
+emit!(one, two, three, four, five);
+emit_notes!(one, two);
+
+fn main() {}

vendor/proc-macro-error2/tests/ui/emit.stderr

@@ -0,0 +1,48 @@
+error: emit!(span, from) test
+ --> tests/ui/emit.rs:3:7
+  |
+3 | emit!(one, two, three, four, five);
+  |       ^^^
+
+error: emit!(span, expr1, expr2) test
+ --> tests/ui/emit.rs:3:12
+  |
+3 | emit!(one, two, three, four, five);
+  |            ^^^
+
+error: emit!(span, single_expr) test
+ --> tests/ui/emit.rs:3:17
+  |
+3 | emit!(one, two, three, four, five);
+  |                 ^^^^^
+
+error: Diagnostic::emit() test
+ --> tests/ui/emit.rs:3:24
+  |
+3 | emit!(one, two, three, four, five);
+  |                        ^^^^
+
+error: emit_call_site_error!(expr) test
+ --> tests/ui/emit.rs:3:1
+  |
+3 | emit!(one, two, three, four, five);
+  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+  |
+  = note: this error originates in the macro `emit` (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
+
+ --> tests/ui/emit.rs:4:13
+  |
+4 | emit_notes!(one, two);
+  |             ^^^

vendor/proc-macro-error2/tests/ui/explicit_span_range.rs

@@ -0,0 +1,5 @@
+use test_crate::*;
+
+explicit_span_range!(one, two, three, four);
+
+fn main() {}

vendor/proc-macro-error2/tests/ui/explicit_span_range.stderr

@@ -0,0 +1,5 @@
+error: explicit SpanRange
+ --> tests/ui/explicit_span_range.rs:3:22
+  |
+3 | explicit_span_range!(one, two, three, four);
+  |                      ^^^^^^^^^^^^^^^

vendor/proc-macro-error2/tests/ui/misuse.rs

@@ -0,0 +1,10 @@
+use proc_macro_error2::abort;
+
+struct Foo;
+
+#[allow(unused)]
+fn foo() {
+    abort!(Foo, "BOOM");
+}
+
+fn main() {}

vendor/proc-macro-error2/tests/ui/misuse.stderr

@@ -0,0 +1,24 @@
+error[E0599]: the method `FIRST_ARG_MUST_EITHER_BE_Span_OR_IMPLEMENT_ToTokens_OR_BE_SpanRange` exists for reference `&Foo`, but its trait bounds were not satisfied
+ --> tests/ui/misuse.rs:7:5
+  |
+3 | struct Foo;
+  | ---------- doesn't satisfy `Foo: quote::to_tokens::ToTokens`
+...
+7 |     abort!(Foo, "BOOM");
+  |     ^^^^^^^^^^^^^^^^^^^ method cannot be called on `&Foo` due to unsatisfied trait bounds
+  |
+  = note: the following trait bounds were not satisfied:
+          `Foo: quote::to_tokens::ToTokens`
+          which is required by `&Foo: ToTokensAsSpanRange`
+note: the trait `quote::to_tokens::ToTokens` must be implemented
+ --> $CARGO/quote-1.0.37/src/to_tokens.rs
+  |
+  | pub trait ToTokens {
+  | ^^^^^^^^^^^^^^^^^^
+  = help: items from traits can only be used if the trait is implemented and in scope
+  = note: the following traits define an item `FIRST_ARG_MUST_EITHER_BE_Span_OR_IMPLEMENT_ToTokens_OR_BE_SpanRange`, perhaps you need to implement one of them:
+          candidate #1: `Span2AsSpanRange`
+          candidate #2: `SpanAsSpanRange`
+          candidate #3: `SpanRangeAsSpanRange`
+          candidate #4: `ToTokensAsSpanRange`
+  = note: this error originates in the macro `$crate::diagnostic` which comes from the expansion of the macro `abort` (in Nightly builds, run with -Z macro-backtrace for more info)

vendor/proc-macro-error2/tests/ui/multiple_tokens.rs

@@ -0,0 +1,4 @@
+#[test_crate::multiple_tokens]
+type T = ();
+
+fn main() {}

vendor/proc-macro-error2/tests/ui/multiple_tokens.stderr

@@ -0,0 +1,5 @@
+error: ...
+ --> tests/ui/multiple_tokens.rs:2:1
+  |
+2 | type T = ();
+  | ^^^^^^^^^^^^

vendor/proc-macro-error2/tests/ui/not_proc_macro.rs

@@ -0,0 +1,4 @@
+use proc_macro_error2::proc_macro_error;
+
+#[proc_macro_error]
+fn main() {}

vendor/proc-macro-error2/tests/ui/not_proc_macro.stderr

@@ -0,0 +1,9 @@
+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)]
+ --> tests/ui/not_proc_macro.rs:3:1
+  |
+3 | #[proc_macro_error]
+  | ^^^^^^^^^^^^^^^^^^^
+  |
+  = note: this error originates in the attribute macro `proc_macro_error` (in Nightly builds, run with -Z macro-backtrace for more info)

vendor/proc-macro-error2/tests/ui/option_ext.rs

@@ -0,0 +1,5 @@
+use test_crate::*;
+
+option_ext!(one, two);
+
+fn main() {}

vendor/proc-macro-error2/tests/ui/option_ext.stderr

@@ -0,0 +1,7 @@
+error: Option::expect_or_abort() test
+ --> tests/ui/option_ext.rs:3:1
+  |
+3 | option_ext!(one, two);
+  | ^^^^^^^^^^^^^^^^^^^^^
+  |
+  = note: this error originates in the macro `option_ext` (in Nightly builds, run with -Z macro-backtrace for more info)

vendor/proc-macro-error2/tests/ui/result_ext.rs

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

vendor/proc-macro-error2/tests/ui/result_ext.stderr

@@ -0,0 +1,11 @@
+error: Result::unwrap_or_abort() test
+ --> tests/ui/result_ext.rs:3:25
+  |
+3 | result_unwrap_or_abort!(one, two);
+  |                         ^^^
+
+error: BOOM: Result::expect_or_abort() test
+ --> tests/ui/result_ext.rs:4:25
+  |
+4 | result_expect_or_abort!(one, two);
+  |                         ^^^

vendor/proc-macro-error2/tests/ui/to_tokens_span.rs

@@ -0,0 +1,5 @@
+use test_crate::*;
+
+to_tokens_span!(std::option::Option);
+
+fn main() {}

vendor/proc-macro-error2/tests/ui/to_tokens_span.stderr

@@ -0,0 +1,11 @@
+error: whole type
+ --> tests/ui/to_tokens_span.rs:3:17
+  |
+3 | to_tokens_span!(std::option::Option);
+  |                 ^^^^^^^^^^^^^^^^^^^
+
+error: explicit .span()
+ --> tests/ui/to_tokens_span.rs:3:17
+  |
+3 | to_tokens_span!(std::option::Option);
+  |                 ^^^

vendor/proc-macro-error2/tests/ui/unknown_setting.rs

@@ -0,0 +1,4 @@
+use proc_macro_error2::proc_macro_error;
+
+#[proc_macro_error(allow_not_macro, assert_unwind_safe, trololo)]
+fn main() {}

vendor/proc-macro-error2/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`
+ --> tests/ui/unknown_setting.rs:3:57
+  |
+3 | #[proc_macro_error(allow_not_macro, assert_unwind_safe, trololo)]
+  |                                                         ^^^^^^^

vendor/proc-macro-error2/tests/ui/unrelated_panic.rs

@@ -0,0 +1,5 @@
+use test_crate::*;
+
+unrelated_panic!();
+
+fn main() {}

vendor/proc-macro-error2/tests/ui/unrelated_panic.stderr

@@ -0,0 +1,7 @@
+error: proc macro panicked
+ --> tests/ui/unrelated_panic.rs:3:1
+  |
+3 | unrelated_panic!();
+  | ^^^^^^^^^^^^^^^^^^
+  |
+  = help: message: unrelated panic test