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/pulldown-cmark/tests/html.rs

@@ -0,0 +1,351 @@
+// Tests for HTML spec.
+#![cfg(feature = "html")]
+
+use pulldown_cmark::{html, BrokenLink, Options, Parser};
+
+#[test]
+fn html_test_1() {
+    let original = r##"Little header
+
+<script type="text/js">
+function some_func() {
+console.log("teeeest");
+}
+
+
+function another_func() {
+console.log("fooooo");
+}
+</script>"##;
+    let expected = r##"<p>Little header</p>
+<script type="text/js">
+function some_func() {
+console.log("teeeest");
+}
+
+
+function another_func() {
+console.log("fooooo");
+}
+</script>"##;
+
+    let mut s = String::new();
+    html::push_html(&mut s, Parser::new(original));
+    assert_eq!(expected, s);
+}
+
+#[test]
+fn html_test_2() {
+    let original = r##"Little header
+
+<script
+type="text/js">
+function some_func() {
+console.log("teeeest");
+}
+
+
+function another_func() {
+console.log("fooooo");
+}
+</script>"##;
+    let expected = r##"<p>Little header</p>
+<script
+type="text/js">
+function some_func() {
+console.log("teeeest");
+}
+
+
+function another_func() {
+console.log("fooooo");
+}
+</script>"##;
+
+    let mut s = String::new();
+    html::push_html(&mut s, Parser::new(original));
+    assert_eq!(expected, s);
+}
+
+#[test]
+fn html_test_3() {
+    let original = r##"Little header
+
+<?
+<div></div>
+<p>Useless</p>
+?>"##;
+    let expected = r##"<p>Little header</p>
+<?
+<div></div>
+<p>Useless</p>
+?>"##;
+
+    let mut s = String::new();
+    html::push_html(&mut s, Parser::new(original));
+    assert_eq!(expected, s);
+}
+
+#[test]
+fn html_test_4() {
+    let original = r##"Little header
+
+<!--
+<div></div>
+<p>Useless</p>
+-->"##;
+    let expected = r##"<p>Little header</p>
+<!--
+<div></div>
+<p>Useless</p>
+-->"##;
+
+    let mut s = String::new();
+    html::push_html(&mut s, Parser::new(original));
+    assert_eq!(expected, s);
+}
+
+#[test]
+fn html_test_5() {
+    let original = r##"Little header
+
+<![CDATA[
+<div></div>
+<p>Useless</p>
+]]>"##;
+    let expected = r##"<p>Little header</p>
+<![CDATA[
+<div></div>
+<p>Useless</p>
+]]>"##;
+
+    let mut s = String::new();
+    html::push_html(&mut s, Parser::new(original));
+    assert_eq!(expected, s);
+}
+
+#[test]
+fn html_test_6() {
+    let original = r##"Little header
+
+<!X
+Some things are here...
+>"##;
+    let expected = r##"<p>Little header</p>
+<!X
+Some things are here...
+>"##;
+
+    let mut s = String::new();
+    html::push_html(&mut s, Parser::new(original));
+    assert_eq!(expected, s);
+}
+
+#[test]
+fn html_test_7() {
+    let original = r##"Little header
+-----------
+
+<script>
+function some_func() {
+console.log("teeeest");
+}
+
+
+function another_func() {
+console.log("fooooo");
+}
+</script>"##;
+    let expected = r##"<h2>Little header</h2>
+<script>
+function some_func() {
+console.log("teeeest");
+}
+
+
+function another_func() {
+console.log("fooooo");
+}
+</script>"##;
+
+    let mut s = String::new();
+    html::push_html(&mut s, Parser::new(original));
+    assert_eq!(expected, s);
+}
+
+#[test]
+fn html_test_8() {
+    let original = "A | B\n---|---\nfoo | bar";
+    let expected = r##"<table><thead><tr><th>A</th><th>B</th></tr></thead><tbody>
+<tr><td>foo</td><td>bar</td></tr>
+</tbody></table>
+"##;
+
+    let mut s = String::new();
+    let mut opts = Options::empty();
+    opts.insert(Options::ENABLE_TABLES);
+    html::push_html(&mut s, Parser::new_ext(original, opts));
+    assert_eq!(expected, s);
+}
+
+#[test]
+fn html_test_9() {
+    let original = "---";
+    let expected = "<hr />\n";
+
+    let mut s = String::new();
+    html::push_html(&mut s, Parser::new(original));
+    assert_eq!(expected, s);
+}
+
+#[test]
+fn html_test_10() {
+    let original = "* * *";
+    let expected = "<hr />\n";
+
+    let mut s = String::new();
+    html::push_html(&mut s, Parser::new(original));
+    assert_eq!(expected, s);
+}
+
+#[test]
+fn html_test_11() {
+    let original = "hi ~~no~~";
+    let expected = "<p>hi ~~no~~</p>\n";
+
+    let mut s = String::new();
+    html::push_html(&mut s, Parser::new(original));
+    assert_eq!(expected, s);
+}
+
+#[test]
+fn html_test_broken_callback() {
+    let original = r##"[foo],
+[bar],
+[baz],
+
+   [baz]: https://example.org
+"##;
+
+    let expected = r##"<p><a href="https://replaced.example.org" title="some title">foo</a>,
+[bar],
+<a href="https://example.org">baz</a>,</p>
+"##;
+
+    use pulldown_cmark::{html, Options, Parser};
+
+    let mut s = String::new();
+
+    let mut callback = |broken_link: BrokenLink| {
+        if &*broken_link.reference == "foo" || &*broken_link.reference == "baz" {
+            Some(("https://replaced.example.org".into(), "some title".into()))
+        } else {
+            None
+        }
+    };
+
+    let p = Parser::new_with_broken_link_callback(original, Options::empty(), Some(&mut callback));
+    html::push_html(&mut s, p);
+
+    assert_eq!(expected, s);
+}
+
+#[test]
+fn newline_in_code() {
+    let originals = ["`\n `x", "` \n`x"];
+    let expected = "<p><code>  </code>x</p>\n";
+
+    for original in originals {
+        let mut s = String::new();
+        html::push_html(&mut s, Parser::new(original));
+        assert_eq!(expected, s);
+    }
+}
+
+#[test]
+fn newline_start_end_of_code() {
+    let original = "`\nx\n`x";
+    let expected = "<p><code>x</code>x</p>\n";
+
+    let mut s = String::new();
+    html::push_html(&mut s, Parser::new(original));
+    assert_eq!(expected, s);
+}
+
+// https://github.com/raphlinus/pulldown-cmark/issues/715
+
+#[test]
+fn trim_space_and_tab_at_end_of_paragraph() {
+    let original = "one\ntwo \t";
+    let expected = "<p>one\ntwo</p>\n";
+
+    let mut s = String::new();
+    html::push_html(&mut s, Parser::new(original));
+    assert_eq!(expected, s);
+}
+
+#[test]
+fn newline_within_code() {
+    let originals = ["`\nx \ny\n`x", "`x \ny`x", "`x\n y`x"];
+    let expected = "<p><code>x  y</code>x</p>\n";
+
+    for original in originals {
+        let mut s = String::new();
+        html::push_html(&mut s, Parser::new(original));
+        assert_eq!(expected, s);
+    }
+}
+
+#[test]
+fn trim_space_tab_nl_at_end_of_paragraph() {
+    let original = "one\ntwo \t\n";
+    let expected = "<p>one\ntwo</p>\n";
+
+    let mut s = String::new();
+    html::push_html(&mut s, Parser::new(original));
+    assert_eq!(expected, s);
+}
+
+#[test]
+fn trim_space_nl_at_end_of_paragraph() {
+    let original = "one\ntwo \n";
+    let expected = "<p>one\ntwo</p>\n";
+
+    let mut s = String::new();
+    html::push_html(&mut s, Parser::new(original));
+    assert_eq!(expected, s);
+}
+
+#[test]
+fn trim_space_before_soft_break() {
+    let original = "one \ntwo";
+    let expected = "<p>one\ntwo</p>\n";
+
+    let mut s = String::new();
+    html::push_html(&mut s, Parser::new(original));
+    assert_eq!(expected, s);
+}
+
+// Can't easily use regression.txt due to newline normalization.
+#[test]
+fn issue_819() {
+    let original = [
+        "# \\", "# \\\n", "# \\\n\n", "# \\\r\n", "# \\\r\n\r\n", "# \\\n\r\n", "# \\\r\n\n"
+    ];
+    let expected = "<h1>\\</h1>";
+
+    for orig in original {
+        let mut s = String::new();
+        html::push_html(&mut s, Parser::new(orig));
+        // Trailing newline doesn't matter. Just the actual HTML.
+        assert_eq!(expected, s.trim_end_matches('\n'));
+    }
+    for orig in original {
+        let mut s = String::new();
+        let mut opts = Options::empty();
+        opts.insert(Options::ENABLE_HEADING_ATTRIBUTES);
+        html::push_html(&mut s, Parser::new_ext(orig, opts));
+        // Trailing newline doesn't matter. Just the actual HTML.
+        assert_eq!(expected, s.trim_end_matches('\n'));
+    }
+}