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/round_trip/section_flags.rs

@@ -0,0 +1,89 @@
+#![cfg(all(feature = "read", feature = "write"))]
+
+use object::read::{Object, ObjectSection};
+use object::{read, write};
+use object::{Architecture, BinaryFormat, Endianness, SectionFlags, SectionKind};
+
+#[test]
+fn coff_x86_64_section_flags() {
+    let mut object =
+        write::Object::new(BinaryFormat::Coff, Architecture::X86_64, Endianness::Little);
+
+    let section = object.add_section(Vec::new(), b".text".to_vec(), SectionKind::Text);
+    object.section_mut(section).flags = SectionFlags::Coff {
+        characteristics: object::pe::IMAGE_SCN_MEM_WRITE,
+    };
+
+    let bytes = object.write().unwrap();
+
+    let object = read::File::parse(&*bytes).unwrap();
+    assert_eq!(object.format(), BinaryFormat::Coff);
+    assert_eq!(object.architecture(), Architecture::X86_64);
+
+    let mut sections = object.sections();
+    let section = sections.next().unwrap();
+    assert_eq!(section.name(), Ok(".text"));
+    assert_eq!(
+        section.flags(),
+        SectionFlags::Coff {
+            characteristics: object::pe::IMAGE_SCN_MEM_WRITE | object::pe::IMAGE_SCN_ALIGN_1BYTES,
+        }
+    );
+}
+
+#[test]
+fn elf_x86_64_section_flags() {
+    let mut object =
+        write::Object::new(BinaryFormat::Elf, Architecture::X86_64, Endianness::Little);
+
+    let section = object.add_section(Vec::new(), b".text".to_vec(), SectionKind::Text);
+    object.section_mut(section).flags = SectionFlags::Elf {
+        sh_flags: object::elf::SHF_WRITE.into(),
+    };
+
+    let bytes = object.write().unwrap();
+
+    let object = read::File::parse(&*bytes).unwrap();
+    assert_eq!(object.format(), BinaryFormat::Elf);
+    assert_eq!(object.architecture(), Architecture::X86_64);
+
+    let mut sections = object.sections();
+    let section = sections.next().unwrap();
+    assert_eq!(section.name(), Ok(".text"));
+    assert_eq!(
+        section.flags(),
+        SectionFlags::Elf {
+            sh_flags: object::elf::SHF_WRITE.into(),
+        }
+    );
+}
+
+#[test]
+fn macho_x86_64_section_flags() {
+    let mut object = write::Object::new(
+        BinaryFormat::MachO,
+        Architecture::X86_64,
+        Endianness::Little,
+    );
+
+    let section = object.add_section(Vec::new(), b".text".to_vec(), SectionKind::Text);
+    object.section_mut(section).flags = SectionFlags::MachO {
+        flags: object::macho::S_ATTR_SELF_MODIFYING_CODE,
+    };
+
+    let bytes = object.write().unwrap();
+
+    let object = read::File::parse(&*bytes).unwrap();
+    assert_eq!(object.format(), BinaryFormat::MachO);
+    assert_eq!(object.architecture(), Architecture::X86_64);
+
+    let mut sections = object.sections();
+    let section = sections.next().unwrap();
+    assert_eq!(section.name(), Ok(".text"));
+    assert_eq!(
+        section.flags(),
+        SectionFlags::MachO {
+            flags: object::macho::S_ATTR_SELF_MODIFYING_CODE,
+        }
+    );
+}