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/litrs/src/tests.rs

@@ -0,0 +1,355 @@
+use crate::Literal;
+
+
+#[test]
+fn empty() {
+    assert_err!(Literal, "", Empty, None);
+}
+
+#[test]
+fn invalid_literals() {
+    assert_err_single!(Literal::parse("."), InvalidLiteral, None);
+    assert_err_single!(Literal::parse("+"), InvalidLiteral, None);
+    assert_err_single!(Literal::parse("-"), InvalidLiteral, None);
+    assert_err_single!(Literal::parse("e"), InvalidLiteral, None);
+    assert_err_single!(Literal::parse("e8"), InvalidLiteral, None);
+    assert_err_single!(Literal::parse("f32"), InvalidLiteral, None);
+    assert_err_single!(Literal::parse("foo"), InvalidLiteral, None);
+    assert_err_single!(Literal::parse("inf"), InvalidLiteral, None);
+    assert_err_single!(Literal::parse("nan"), InvalidLiteral, None);
+    assert_err_single!(Literal::parse("NaN"), InvalidLiteral, None);
+    assert_err_single!(Literal::parse("NAN"), InvalidLiteral, None);
+    assert_err_single!(Literal::parse("_2.7"), InvalidLiteral, None);
+    assert_err_single!(Literal::parse(".5"), InvalidLiteral, None);
+}
+
+#[test]
+fn misc() {
+    assert_err_single!(Literal::parse("0x44.5"), UnexpectedChar, 4..6);
+    assert_err_single!(Literal::parse("a"), InvalidLiteral, None);
+    assert_err_single!(Literal::parse(";"), InvalidLiteral, None);
+    assert_err_single!(Literal::parse("0;"), UnexpectedChar, 1);
+    assert_err_single!(Literal::parse(" 0"), InvalidLiteral, None);
+    assert_err_single!(Literal::parse("0 "), UnexpectedChar, 1);
+    assert_err_single!(Literal::parse("_"), InvalidLiteral, None);
+    assert_err_single!(Literal::parse("_3"), InvalidLiteral, None);
+    assert_err_single!(Literal::parse("a_123"), InvalidLiteral, None);
+    assert_err_single!(Literal::parse("B_123"), InvalidLiteral, None);
+}
+
+macro_rules! assert_no_panic {
+    ($input:expr) => {
+        let arr = $input;
+        let input = std::str::from_utf8(&arr).expect("not unicode");
+        let res = std::panic::catch_unwind(move || {
+            let _ = Literal::parse(input);
+            let _ = crate::BoolLit::parse(input);
+            let _ = crate::IntegerLit::parse(input);
+            let _ = crate::FloatLit::parse(input);
+            let _ = crate::CharLit::parse(input);
+            let _ = crate::StringLit::parse(input);
+            let _ = crate::ByteLit::parse(input);
+            let _ = crate::ByteStringLit::parse(input);
+        });
+
+        if let Err(e) = res {
+            println!("\n!!! panic for: {:?}", input);
+            std::panic::resume_unwind(e);
+        }
+    };
+}
+
+#[test]
+#[ignore]
+fn never_panic_up_to_3() {
+    for a in 0..128 {
+        assert_no_panic!([a]);
+        for b in 0..128 {
+            assert_no_panic!([a, b]);
+            for c in 0..128 {
+                assert_no_panic!([a, b, c]);
+            }
+        }
+    }
+}
+
+// This test takes super long in debug mode, but in release mode it's fine.
+#[test]
+#[ignore]
+fn never_panic_len_4() {
+    for a in 0..128 {
+        for b in 0..128 {
+            for c in 0..128 {
+                for d in 0..128 {
+                    assert_no_panic!([a, b, c, d]);
+                }
+            }
+        }
+    }
+}
+
+#[cfg(feature = "proc-macro2")]
+#[test]
+fn proc_macro() {
+    use std::convert::TryFrom;
+
+    use proc_macro2::{
+        self as pm2, Delimiter, Group, Ident, Punct, Spacing, Span, TokenStream, TokenTree,
+    };
+
+    use crate::{
+        err::TokenKind, BoolLit, ByteLit, ByteStringLit, CharLit, FloatLit, IntegerLit, StringLit,
+    };
+
+
+    macro_rules! assert_invalid_token {
+        ($input:expr, expected: $expected:path, actual: $actual:path $(,)?) => {
+            let err = $input.unwrap_err();
+            if err.expected != $expected {
+                panic!(
+                    "err.expected was expected to be {:?}, but is {:?}",
+                    $expected, err.expected,
+                );
+            }
+            if err.actual != $actual {
+                panic!(
+                    "err.actual was expected to be {:?}, but is {:?}",
+                    $actual, err.actual
+                );
+            }
+        };
+    }
+
+
+    let pm_u16_lit = pm2::Literal::u16_suffixed(2700);
+    let pm_i16_lit = pm2::Literal::i16_unsuffixed(3912);
+    let pm_f32_lit = pm2::Literal::f32_unsuffixed(3.14);
+    let pm_f64_lit = pm2::Literal::f64_suffixed(99.3);
+    let pm_string_lit = pm2::Literal::string("hello 🦊");
+    let pm_bytestr_lit = pm2::Literal::byte_string(b"hello \nfoxxo");
+    let pm_char_lit = pm2::Literal::character('🦀');
+
+    let u16_lit = Literal::parse("2700u16".to_string()).unwrap();
+    let i16_lit = Literal::parse("3912".to_string()).unwrap();
+    let f32_lit = Literal::parse("3.14".to_string()).unwrap();
+    let f64_lit = Literal::parse("99.3f64".to_string()).unwrap();
+    let string_lit = Literal::parse(r#""hello 🦊""#.to_string()).unwrap();
+    let bytestr_lit = Literal::parse(r#"b"hello \nfoxxo""#.to_string()).unwrap();
+    let char_lit = Literal::parse("'🦀'".to_string()).unwrap();
+
+    assert_eq!(Literal::from(&pm_u16_lit), u16_lit);
+    assert_eq!(Literal::from(&pm_i16_lit), i16_lit);
+    assert_eq!(Literal::from(&pm_f32_lit), f32_lit);
+    assert_eq!(Literal::from(&pm_f64_lit), f64_lit);
+    assert_eq!(Literal::from(&pm_string_lit), string_lit);
+    assert_eq!(Literal::from(&pm_bytestr_lit), bytestr_lit);
+    assert_eq!(Literal::from(&pm_char_lit), char_lit);
+
+
+    let group = TokenTree::from(Group::new(Delimiter::Brace, TokenStream::new()));
+    let punct = TokenTree::from(Punct::new(':', Spacing::Alone));
+    let ident = TokenTree::from(Ident::new("peter", Span::call_site()));
+
+    assert_eq!(
+        Literal::try_from(TokenTree::Literal(pm2::Literal::string("hello 🦊"))).unwrap(),
+        Literal::String(StringLit::parse(r#""hello 🦊""#.to_string()).unwrap()),
+    );
+    assert_invalid_token!(
+        Literal::try_from(punct.clone()),
+        expected: TokenKind::Literal,
+        actual: TokenKind::Punct,
+    );
+    assert_invalid_token!(
+        Literal::try_from(group.clone()),
+        expected: TokenKind::Literal,
+        actual: TokenKind::Group,
+    );
+    assert_invalid_token!(
+        Literal::try_from(ident.clone()),
+        expected: TokenKind::Literal,
+        actual: TokenKind::Ident,
+    );
+
+
+    assert_eq!(Literal::from(IntegerLit::try_from(pm_u16_lit.clone()).unwrap()), u16_lit);
+    assert_eq!(Literal::from(IntegerLit::try_from(pm_i16_lit.clone()).unwrap()), i16_lit);
+    assert_eq!(Literal::from(FloatLit::try_from(pm_f32_lit.clone()).unwrap()), f32_lit);
+    assert_eq!(Literal::from(FloatLit::try_from(pm_f64_lit.clone()).unwrap()), f64_lit);
+    assert_eq!(Literal::from(StringLit::try_from(pm_string_lit.clone()).unwrap()), string_lit);
+    assert_eq!(
+        Literal::from(ByteStringLit::try_from(pm_bytestr_lit.clone()).unwrap()),
+        bytestr_lit,
+    );
+    assert_eq!(Literal::from(CharLit::try_from(pm_char_lit.clone()).unwrap()), char_lit);
+
+    assert_invalid_token!(
+        StringLit::try_from(pm_u16_lit.clone()),
+        expected: TokenKind::StringLit,
+        actual: TokenKind::IntegerLit,
+    );
+    assert_invalid_token!(
+        StringLit::try_from(pm_f32_lit.clone()),
+        expected: TokenKind::StringLit,
+        actual: TokenKind::FloatLit,
+    );
+    assert_invalid_token!(
+        ByteLit::try_from(pm_bytestr_lit.clone()),
+        expected: TokenKind::ByteLit,
+        actual: TokenKind::ByteStringLit,
+    );
+    assert_invalid_token!(
+        ByteLit::try_from(pm_i16_lit.clone()),
+        expected: TokenKind::ByteLit,
+        actual: TokenKind::IntegerLit,
+    );
+    assert_invalid_token!(
+        IntegerLit::try_from(pm_string_lit.clone()),
+        expected: TokenKind::IntegerLit,
+        actual: TokenKind::StringLit,
+    );
+    assert_invalid_token!(
+        IntegerLit::try_from(pm_char_lit.clone()),
+        expected: TokenKind::IntegerLit,
+        actual: TokenKind::CharLit,
+    );
+
+
+    assert_eq!(
+        Literal::from(IntegerLit::try_from(TokenTree::from(pm_u16_lit.clone())).unwrap()),
+        u16_lit,
+    );
+    assert_eq!(
+        Literal::from(IntegerLit::try_from(TokenTree::from(pm_i16_lit.clone())).unwrap()),
+        i16_lit,
+    );
+    assert_eq!(
+        Literal::from(FloatLit::try_from(TokenTree::from(pm_f32_lit.clone())).unwrap()),
+        f32_lit,
+    );
+    assert_eq!(
+        Literal::from(FloatLit::try_from(TokenTree::from(pm_f64_lit.clone())).unwrap()),
+        f64_lit,
+    );
+    assert_eq!(
+        Literal::from(StringLit::try_from(TokenTree::from(pm_string_lit.clone())).unwrap()),
+        string_lit,
+    );
+    assert_eq!(
+        Literal::from(ByteStringLit::try_from(TokenTree::from(pm_bytestr_lit.clone())).unwrap()),
+        bytestr_lit,
+    );
+    assert_eq!(
+        Literal::from(CharLit::try_from(TokenTree::from(pm_char_lit.clone())).unwrap()),
+        char_lit,
+    );
+
+    assert_invalid_token!(
+        StringLit::try_from(TokenTree::from(pm_u16_lit.clone())),
+        expected: TokenKind::StringLit,
+        actual: TokenKind::IntegerLit,
+    );
+    assert_invalid_token!(
+        StringLit::try_from(TokenTree::from(pm_f32_lit.clone())),
+        expected: TokenKind::StringLit,
+        actual: TokenKind::FloatLit,
+    );
+    assert_invalid_token!(
+        BoolLit::try_from(TokenTree::from(pm_bytestr_lit.clone())),
+        expected: TokenKind::BoolLit,
+        actual: TokenKind::ByteStringLit,
+    );
+    assert_invalid_token!(
+        BoolLit::try_from(TokenTree::from(pm_i16_lit.clone())),
+        expected: TokenKind::BoolLit,
+        actual: TokenKind::IntegerLit,
+    );
+    assert_invalid_token!(
+        IntegerLit::try_from(TokenTree::from(pm_string_lit.clone())),
+        expected: TokenKind::IntegerLit,
+        actual: TokenKind::StringLit,
+    );
+    assert_invalid_token!(
+        IntegerLit::try_from(TokenTree::from(pm_char_lit.clone())),
+        expected: TokenKind::IntegerLit,
+        actual: TokenKind::CharLit,
+    );
+
+    assert_invalid_token!(
+        StringLit::try_from(TokenTree::from(group)),
+        expected: TokenKind::StringLit,
+        actual: TokenKind::Group,
+    );
+    assert_invalid_token!(
+        BoolLit::try_from(TokenTree::from(punct)),
+        expected: TokenKind::BoolLit,
+        actual: TokenKind::Punct,
+    );
+    assert_invalid_token!(
+        FloatLit::try_from(TokenTree::from(ident)),
+        expected: TokenKind::FloatLit,
+        actual: TokenKind::Ident,
+    );
+}
+
+#[cfg(feature = "proc-macro2")]
+#[test]
+fn bool_try_from_tt() {
+    use std::convert::TryFrom;
+
+    use proc_macro2::{Ident, Span, TokenTree};
+
+    use crate::BoolLit;
+
+
+    let ident = |s: &str| Ident::new(s, Span::call_site());
+
+    assert_eq!(BoolLit::try_from(TokenTree::Ident(ident("true"))).unwrap(), BoolLit::True);
+    assert_eq!(BoolLit::try_from(TokenTree::Ident(ident("false"))).unwrap(), BoolLit::False);
+
+    assert!(BoolLit::try_from(TokenTree::Ident(ident("falsex"))).is_err());
+    assert!(BoolLit::try_from(TokenTree::Ident(ident("_false"))).is_err());
+    assert!(BoolLit::try_from(TokenTree::Ident(ident("False"))).is_err());
+    assert!(BoolLit::try_from(TokenTree::Ident(ident("True"))).is_err());
+    assert!(BoolLit::try_from(TokenTree::Ident(ident("ltrue"))).is_err());
+
+
+    assert_eq!(
+        Literal::try_from(TokenTree::Ident(ident("true"))).unwrap(),
+        Literal::Bool(BoolLit::True),
+    );
+    assert_eq!(
+        Literal::try_from(TokenTree::Ident(ident("false"))).unwrap(),
+        Literal::Bool(BoolLit::False),
+    );
+
+    assert!(Literal::try_from(TokenTree::Ident(ident("falsex"))).is_err());
+    assert!(Literal::try_from(TokenTree::Ident(ident("_false"))).is_err());
+    assert!(Literal::try_from(TokenTree::Ident(ident("False"))).is_err());
+    assert!(Literal::try_from(TokenTree::Ident(ident("True"))).is_err());
+    assert!(Literal::try_from(TokenTree::Ident(ident("ltrue"))).is_err());
+}
+
+#[cfg(feature = "proc-macro2")]
+#[test]
+fn invalid_token_display() {
+    use crate::{err::TokenKind, InvalidToken};
+
+    let span = crate::err::Span::Two(proc_macro2::Span::call_site());
+    assert_eq!(
+        InvalidToken {
+            actual: TokenKind::StringLit,
+            expected: TokenKind::FloatLit,
+            span,
+        }.to_string(),
+        r#"expected a float literal (e.g. `3.14`), but found a string literal (e.g. "Ferris")"#,
+    );
+
+    assert_eq!(
+        InvalidToken {
+            actual: TokenKind::Punct,
+            expected: TokenKind::Literal,
+            span,
+        }.to_string(),
+        r#"expected a literal, but found a punctuation character"#,
+    );
+}