feat(loss-harness): sweep the streamed-AU wire shape alongside whole-AU

The Phase-2 gate: more, smaller wire units must not regress FEC recovery.
Adds a GF16 streamed column (three chunk pushes + finish per AU — sentinel
blocks then real totals). Measured: identical to whole-AU at every loss
rate (50/50 through 1/6, the same 25%-budget cliff).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tools/loss-harness/src/main.rs

@@ -31,16 +31,41 @@ fn config(role: Role, scheme: FecScheme, drop_period: u32) -> Config {
     }
 }
 
-/// Returns (frames_completed, frames_attempted) for a loss setting.
+/// Returns (frames_completed, frames_attempted) for a loss setting. `streamed` feeds each AU
-fn run(scheme: FecScheme, drop_period: u32, frames: usize, frame_len: usize) -> (usize, usize) {
+/// through the VIDEO_CAP_STREAMED_AU path (three encoder-chunk pushes + finish — sentinel
+/// blocks then real totals) instead of one whole-AU submit, so the two wire shapes' recovery
+/// curves can be compared directly (the Phase-2 "more, smaller units must not regress FEC" gate).
+fn run(
+    scheme: FecScheme,
+    drop_period: u32,
+    frames: usize,
+    frame_len: usize,
+    streamed: bool,
+) -> (usize, usize) {
     let (h, c) = loopback_pair(drop_period, 0);
     let mut host = Session::new(config(Role::Host, scheme, drop_period), Box::new(h)).unwrap();
     let mut client = Session::new(config(Role::Client, scheme, drop_period), Box::new(c)).unwrap();
 
+    let mut send_wires = |host: &mut Session, wires: Vec<Vec<u8>>| {
+        let refs: Vec<&[u8]> = wires.iter().map(|w| w.as_slice()).collect();
+        host.send_sealed(&refs).unwrap();
+        drop(refs);
+        host.reclaim_wires(wires);
+    };
     let mut completed = 0;
     for f in 0..frames {
         let frame: Vec<u8> = (0..frame_len).map(|b| (b ^ f) as u8).collect();
-        host.submit_frame(&frame, f as u64, 0).unwrap();
+        if streamed {
+            let mut au = host.begin_streamed_frame_at(f as u64, 0, f as u32).unwrap();
+            for chunk in frame.chunks(frame_len / 3 + 1) {
+                let wires = host.seal_streamed_chunk(&mut au, chunk).unwrap();
+                send_wires(&mut host, wires);
+            }
+            let wires = host.seal_streamed_finish(au).unwrap();
+            send_wires(&mut host, wires);
+        } else {
+            host.submit_frame(&frame, f as u64, 0).unwrap();
+        }
         match client.poll_frame() {
             Ok(got) => {
                 if got.data == frame {
@@ -60,22 +85,26 @@ fn main() {
     let periods = [0u32, 32, 16, 8, 6, 4, 3, 2];
 
     println!("punktfunk loss-harness — 25% FEC, {frames} frames of {frame_len} bytes");
-    println!("(GF8 = P1/GameStream-compat, GF16 = P2/wall-breaker)\n");
+    println!("(GF8 = P1/GameStream-compat, GF16 = P2/wall-breaker, strm = streamed-AU wire)\n");
     println!(
-        "{:>10}  {:>9}  {:>14}  {:>14}",
+        "{:>10}  {:>9}  {:>14}  {:>14}  {:>14}",
-        "drop 1/N", "~loss %", "GF8 recovered", "GF16 recovered"
+        "drop 1/N", "~loss %", "GF8 recovered", "GF16 recovered", "GF16 strm"
     );
-    println!("{}", "-".repeat(56));
+    println!("{}", "-".repeat(72));
     for &p in &periods {
         let loss = if p == 0 { 0.0 } else { 100.0 / p as f64 };
-        let (g8, n) = run(FecScheme::Gf8, p, frames, frame_len);
+        let (g8, n) = run(FecScheme::Gf8, p, frames, frame_len, false);
-        let (g16, _) = run(FecScheme::Gf16, p, frames, frame_len);
+        let (g16, _) = run(FecScheme::Gf16, p, frames, frame_len, false);
+        let (g16s, _) = run(FecScheme::Gf16, p, frames, frame_len, true);
         let label = if p == 0 {
             "none".to_string()
         } else {
             format!("1/{p}")
         };
-        println!("{label:>10}  {loss:>8.1}%  {:>11}/{n}  {:>11}/{n}", g8, g16);
+        println!(
+            "{label:>10}  {loss:>8.1}%  {:>11}/{n}  {:>11}/{n}  {:>11}/{n}",
+            g8, g16, g16s
+        );
     }
     println!("\nNote: recovery drops off once per-block loss exceeds the 25% recovery budget.");
 }