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/usb-device/tests/test_class_host/tests.rs

@@ -0,0 +1,323 @@
+use crate::device::*;
+use rand::prelude::*;
+use rusb::{request_type, Direction, Recipient, RequestType, TransferType};
+use std::cmp::max;
+use std::fmt::Write;
+use std::time::{Duration, Instant};
+use usb_device::test_class;
+
+pub type TestFn = fn(&mut DeviceHandles, &mut String) -> ();
+
+const BENCH_TIMEOUT: Duration = Duration::from_secs(10);
+
+macro_rules! tests {
+    { $(fn $name:ident($dev:ident, $out:ident) $body:expr)* } => {
+        pub fn get_tests() -> Vec<(&'static str, TestFn)> {
+            let mut tests: Vec<(&'static str, TestFn)> = Vec::new();
+
+            $(
+                fn $name($dev: &mut DeviceHandles, $out: &mut String) {
+                    $body
+                }
+
+                tests.push((stringify!($name), $name));
+            )*
+
+            tests
+        }
+    }
+}
+
+tests! {
+
+fn control_request(dev, _out) {
+    let mut rng = rand::thread_rng();
+
+    let value: u16 = rng.gen();
+    let index: u16 = rng.gen();
+    let data = random_data(rng.gen_range(0..16));
+
+    let mut expected = [0u8; 8];
+    expected[0] = 0x02_u8 << 5;
+    expected[1] = test_class::REQ_STORE_REQUEST;
+    expected[2..4].copy_from_slice(&value.to_le_bytes());
+    expected[4..6].copy_from_slice(&index.to_le_bytes());
+    expected[6..8].copy_from_slice(&(data.len() as u16).to_le_bytes());
+
+    assert_eq!(
+        dev.write_control(
+            request_type(Direction::Out, RequestType::Vendor, Recipient::Device),
+            test_class::REQ_STORE_REQUEST, value, index,
+            &data, TIMEOUT).expect("control write"),
+        data.len());
+
+    let mut response = [0u8; 8];
+
+    assert_eq!(
+        dev.read_control(
+            request_type(Direction::In, RequestType::Vendor, Recipient::Device),
+            test_class::REQ_READ_BUFFER, 0, 0,
+            &mut response, TIMEOUT).expect("control read"),
+        response.len());
+
+    assert_eq!(&response, &expected);
+}
+
+fn control_data(dev, _out) {
+    for len in &[0, 7, 8, 9, 15, 16, 17] {
+        let data = random_data(*len);
+
+        assert_eq!(
+            dev.write_control(
+                request_type(Direction::Out, RequestType::Vendor, Recipient::Device),
+                test_class::REQ_WRITE_BUFFER, 0, 0,
+                &data, TIMEOUT).unwrap_or_else(|_| panic!("control write len {}", len)),
+            data.len());
+
+        let mut response = vec![0u8; *len];
+
+        assert_eq!(
+            dev.read_control(
+                request_type(Direction::In, RequestType::Vendor, Recipient::Device),
+                test_class::REQ_READ_BUFFER, 0, 0,
+                &mut response, TIMEOUT).unwrap_or_else(|_| panic!("control read len {}", len)),
+            data.len());
+
+        assert_eq!(&response, &data);
+    }
+}
+
+fn control_data_static(dev, _out) {
+    let mut response = [0u8; 257];
+
+    assert_eq!(
+        dev.read_control(
+            request_type(Direction::In, RequestType::Vendor, Recipient::Device),
+            test_class::REQ_READ_LONG_DATA, 0, 0,
+            &mut response, TIMEOUT).expect("control read"),
+        response.len());
+
+    assert_eq!(&response[..], test_class::LONG_DATA);
+}
+
+fn control_error(dev, _out) {
+    let res = dev.write_control(
+        request_type(Direction::Out, RequestType::Vendor, Recipient::Device),
+        test_class::REQ_UNKNOWN, 0, 0,
+        &[], TIMEOUT);
+
+    if res.is_ok() {
+        panic!("unknown control request succeeded");
+    }
+}
+
+fn string_descriptors(dev, _out) {
+    assert_eq!(
+        dev.read_product_string(dev.en_us, &dev.device_descriptor, TIMEOUT)
+            .expect("read product string"),
+        test_class::PRODUCT);
+
+    assert_eq!(
+        dev.read_manufacturer_string(dev.en_us, &dev.device_descriptor, TIMEOUT)
+            .expect("read manufacturer string"),
+        test_class::MANUFACTURER);
+
+    assert_eq!(
+        dev.read_serial_number_string(dev.en_us, &dev.device_descriptor, TIMEOUT)
+            .expect("read serial number string"),
+        test_class::SERIAL_NUMBER);
+
+    assert_eq!(
+        dev.read_string_descriptor(dev.en_us, 4, TIMEOUT)
+            .expect("read custom string"),
+        test_class::CUSTOM_STRING);
+}
+
+fn interface_descriptor(dev, _out) {
+    let iface = dev.config_descriptor
+        .interfaces()
+        .find(|i| i.number() == 0)
+        .expect("interface not found");
+
+    let default_alt_setting = iface.descriptors()
+        .find(|i| i.setting_number() == 0)
+        .expect("default alt setting not found");
+
+    assert_eq!(default_alt_setting.description_string_index(), None);
+    assert_eq!(default_alt_setting.class_code(), 0xff);
+    assert_eq!(default_alt_setting.sub_class_code(), 0x00);
+
+    let second_alt_setting = iface.descriptors()
+        .find(|i| i.setting_number() == 1)
+        .expect("second alt setting not found");
+
+    assert_eq!(second_alt_setting.class_code(), 0xff);
+    assert_eq!(second_alt_setting.sub_class_code(), 0x01);
+
+    let string_index = second_alt_setting.description_string_index()
+        .expect("second alt setting string is undefined");
+
+    assert_eq!(
+        dev.read_string_descriptor(dev.en_us, string_index, TIMEOUT)
+            .expect("read interface string"),
+        test_class::INTERFACE_STRING);
+}
+
+fn iso_endpoint_descriptors(dev, _out) {
+    // Tests that an isochronous endpoint descriptor is present in the first
+    // alternate setting, but not in the default setting.
+    let iface = dev.config_descriptor
+        .interfaces()
+        .find(|i| i.number() == 0)
+        .expect("interface not found");
+
+    let mut iso_ep_count = 0;
+    for iface_descriptor in iface.descriptors() {
+        if iface_descriptor.setting_number() == 0 {
+            // Default setting - no isochronous endpoints allowed.  Per USB 2.0
+            // spec rev 2.0, 5.6.3 Isochronous Transfer Packet Size Constraints:
+            //
+            // All device default interface settings must not include any
+            // isochronous endpoints with non-zero data payload sizes (specified
+            // via wMaxPacketSize in the endpoint descriptor)
+            let issue = iface_descriptor
+                .endpoint_descriptors()
+                .find(|ep| ep.transfer_type() == TransferType::Isochronous
+                    && ep.max_packet_size() != 0);
+            if let Some(ep) = issue {
+                panic!("Endpoint {} is isochronous and in the default setting",
+                    ep.number());
+            }
+        } else {
+            iso_ep_count += iface_descriptor.endpoint_descriptors()
+                .filter(|ep| ep.transfer_type() == TransferType::Isochronous)
+                .count();
+        }
+    }
+    assert!(iso_ep_count > 0, "At least one isochronous endpoint is expected");
+}
+
+fn bulk_loopback(dev, _out) {
+    let mut lens = vec![0, 1, 2, 32, 63, 64, 65, 127, 128, 129];
+    if dev.is_high_speed() {
+        lens.extend([255, 256, 257, 511, 512, 513, 1023, 1024, 1025]);
+    }
+
+    let max_packet_size: usize = dev.bulk_max_packet_size().into();
+    for len in &lens {
+        let data = random_data(*len);
+
+        assert_eq!(
+            dev.write_bulk(0x01, &data, TIMEOUT)
+                .unwrap_or_else(|_| panic!("bulk write len {}", len)),
+            data.len(),
+            "bulk write len {}", len);
+
+        if *len > 0 && *len % max_packet_size == 0 {
+            assert_eq!(
+                dev.write_bulk(0x01, &[], TIMEOUT)
+                    .expect("bulk write zero-length packet"),
+                0,
+                "bulk write zero-length packet");
+        }
+
+        // Prevent libusb from instantaneously reading an empty packet on Windows when
+        // zero-sized buffer is passed.
+        let mut response = vec![0u8; max(*len, 1)];
+
+        assert_eq!(
+            dev.read_bulk(0x81, &mut response, TIMEOUT)
+                .unwrap_or_else(|_| panic!("bulk read len {}", len)),
+            data.len(),
+            "bulk read len {}", len);
+
+        assert_eq!(&response[..*len], &data[..]);
+    }
+}
+
+fn interrupt_loopback(dev, _out) {
+    for len in &[0, 1, 2, 15, 31] {
+        let data = random_data(*len);
+
+        assert_eq!(
+            dev.write_interrupt(0x02, &data, TIMEOUT)
+                .unwrap_or_else(|_| panic!("interrupt write len {}", len)),
+            data.len(),
+            "interrupt write len {}", len);
+
+        // Prevent libusb from instantaneously reading an empty packet on Windows when
+        // zero-sized buffer is passed.
+        let mut response = vec![0u8; max(*len, 1)];
+
+        assert_eq!(
+            dev.read_interrupt(0x82, &mut response, TIMEOUT)
+                .unwrap_or_else(|_| panic!("interrupt read len {}", len)),
+            data.len(),
+            "interrupt read len {}", len);
+
+        assert_eq!(&response[..*len], &data[..]);
+    }
+}
+
+fn bench_bulk_write(dev, out) {
+    run_bench(dev, out, |data| {
+        assert_eq!(
+            dev.write_bulk(0x01, data, BENCH_TIMEOUT)
+                .expect("bulk write"),
+            data.len(),
+            "bulk write");
+    });
+}
+
+fn bench_bulk_read(dev, out) {
+    run_bench(dev, out, |data| {
+        assert_eq!(
+            dev.read_bulk(0x81, data, BENCH_TIMEOUT)
+                .expect("bulk read"),
+            data.len(),
+            "bulk read");
+    });
+}
+
+}
+
+fn run_bench(dev: &DeviceHandles, out: &mut String, f: impl Fn(&mut [u8])) {
+    const TRANSFER_BYTES: usize = 64 * 1024;
+    const TRANSFERS: usize = 16;
+    const TOTAL_BYTES: usize = TRANSFER_BYTES * TRANSFERS;
+
+    dev.write_control(
+        request_type(Direction::Out, RequestType::Vendor, Recipient::Device),
+        test_class::REQ_SET_BENCH_ENABLED,
+        1,
+        0,
+        &[],
+        TIMEOUT,
+    )
+    .expect("enable bench mode");
+
+    let mut data = random_data(TRANSFER_BYTES);
+
+    let start = Instant::now();
+
+    for _ in 0..TRANSFERS {
+        f(&mut data);
+    }
+
+    let elapsed = start.elapsed();
+    let elapsed = elapsed.as_secs() as f64 + (elapsed.subsec_micros() as f64) * 0.000_001;
+    let throughput = (TOTAL_BYTES * 8) as f64 / 1_000_000.0 / elapsed;
+
+    writeln!(
+        out,
+        "  {} transfers of {} bytes in {:.3}s -> {:.3}Mbit/s",
+        TRANSFERS, TRANSFER_BYTES, elapsed, throughput
+    )
+    .expect("write failed");
+}
+
+fn random_data(len: usize) -> Vec<u8> {
+    let mut data = vec![0u8; len];
+    rand::thread_rng().fill(data.as_mut_slice());
+    data
+}