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/object/tests/read/macho.rs

@@ -0,0 +1,49 @@
+#[cfg(feature = "std")]
+use object::{Object, ObjectSection as _};
+
+// Test that we can read compressed sections in Mach-O files as produced
+// by the Go compiler.
+#[cfg(feature = "std")]
+#[test]
+fn test_go_macho() {
+    let macho_testfiles = std::path::Path::new("testfiles/macho");
+
+    // Section names we expect to find, whether they should be
+    // compressed, and the actual name of the section in the file.
+    const EXPECTED: &[(&str, bool, &str)] = &[
+        (".debug_abbrev", true, "__zdebug_abbrev"),
+        (".debug_gdb_scripts", false, "__debug_gdb_scri"),
+        (".debug_ranges", true, "__zdebug_ranges"),
+        ("__data", false, "__data"),
+    ];
+
+    for file in &["go-aarch64", "go-x86_64"] {
+        let path = macho_testfiles.join(file);
+        let file = std::fs::File::open(path).unwrap();
+        let reader = object::read::ReadCache::new(file);
+        let object = object::read::File::parse(&reader).unwrap();
+        for &(name, compressed, actual_name) in EXPECTED {
+            let section = object.section_by_name(name).unwrap();
+            assert_eq!(section.name(), Ok(actual_name));
+            let compressed_file_range = section.compressed_file_range().unwrap();
+            let size = section.size();
+            if compressed {
+                assert_eq!(
+                    compressed_file_range.format,
+                    object::CompressionFormat::Zlib
+                );
+                assert_eq!(compressed_file_range.compressed_size, size - 12);
+                assert!(
+                    compressed_file_range.uncompressed_size > compressed_file_range.compressed_size,
+                    "decompressed size is greater than compressed size"
+                );
+            } else {
+                assert_eq!(
+                    compressed_file_range.format,
+                    object::CompressionFormat::None
+                );
+                assert_eq!(compressed_file_range.compressed_size, size);
+            }
+        }
+    }
+}