feat(quic-interop): alias sim-driven testcases + document unsupported ones

The quic-interop-runner exposes several testcases that drive the same
client logic but vary the network conditions injected by the ns-3 sim.
These don't need new client code on our side — they exercise the
existing handshake / transfer paths under loss / corruption / high-RTT /
cross-traffic, which is exactly the bug-finding signal we want.

Aliases added:
  - transferloss, transfercorruption, longrtt, goodput, crosstraffic
    → transfer (H3 GET against varying sim configs)
  - handshakeloss → handshake

Plan doc now lists every standard testcase and either marks it landed,
aliased, or explicitly unsupported with a written reason — so anyone
returning to this knows what's left and why each gap exists. Unsupported
set covers: versionnegotiation (writer hard-codes V1), resumption /
zerortt (no session ticket / 0-RTT), keyupdate (no KEY_PHASE handling),
retry (parser exists but not wired to feed-loop), rebinding-* (no client
migration), amplificationlimit (server-side), blackhole (inverse test),
ipv6 (UdpSocket v6 path unverified).

https://claude.ai/code/session_01HcvfQq1ttPV9PkRoJb4nyT

quic/interop/plans/2026-05-06-interop-runner.md

@@ -66,6 +66,30 @@ Inspect `./logs/<run>/client_qlog/*.qlog` in qvis when something breaks.
 - `multiplexing` testcase: same as `transfer` but issues each GET in a
   parallel `coroutineScope { async { … } }` so the request streams
   genuinely overlap on the wire (what tshark verifies).
+- Aliased sim-driven testcases — these reuse the same client code paths;
+  the runner injects the network condition via the ns-3 sim. Failures
+  here are exactly the bug-finding signal we want, since they exercise
+  loss recovery / RTT estimator / congestion behaviour against real peers:
+  - `transferloss` → transfer (random packet loss)
+  - `transfercorruption` → transfer (random bit-flip; AEAD AUTH FAIL → drop + retransmit)
+  - `longrtt` → transfer (emulated high-latency link)
+  - `goodput` → transfer (throughput floor)
+  - `crosstraffic` → transfer (competing UDP flows on the same link)
+  - `handshakeloss` → handshake (loss during handshake — tests CRYPTO retransmit)
+
+## Explicitly unsupported testcases (return 127, runner skips)
+
+| Testcase | Reason |
+|---|---|
+| `versionnegotiation` | `QuicConnectionWriter` hard-codes `QuicVersion.V1`; needs a configurable initial version + VN-response retry path |
+| `resumption` | session ticket parsing + persistence not yet implemented |
+| `zerortt` | depends on `resumption` + early-data path |
+| `keyupdate` | KEY_PHASE bit handling not yet implemented in 1-RTT |
+| `retry` | `RetryPacket` parses but isn't fully wired into the connection feed-loop yet — claiming support without verifying would mask bugs |
+| `rebinding-port`, `rebinding-addr` | client-side connection migration (re-bind UDP socket, NEW_CONNECTION_ID rotation) not implemented |
+| `amplificationlimit` | server-side test, N/A for client role |
+| `blackhole` | inverse test (verifies we *fail* on dead network in bounded time); needs special handling |
+| `ipv6` | `UdpSocket` IPv6 path not exercised; risky to claim without testing |
 
 ## Phase 1a — landed 2026-05-06
 

quic/interop/src/main/kotlin/com/vitorpamplona/quic/interop/runner/InteropClient.kt

@@ -86,8 +86,9 @@ fun main() {
             // Both `handshake` and `chacha20` only require the handshake to
             // complete; `chacha20` adds the constraint that we offered only
             // ChaCha20-Poly1305 (verified by the runner via tshark on the
-            // sim's pcap, decrypted using SSLKEYLOGFILE).
-            "handshake", "chacha20" -> {
+            // sim's pcap, decrypted using SSLKEYLOGFILE). `handshakeloss`
+            // is the same client behaviour against a lossy sim.
+            "handshake", "chacha20", "handshakeloss" -> {
                 runHandshakeTest(requests, cipherSuites, keyLogPath)
             }
 
@@ -95,8 +96,16 @@ fun main() {
             // write each body to $DOWNLOADS/<basename>. `multiplexing`
             // additionally requires the requests to be sent in parallel on
             // separate streams (the runner verifies via tshark that the
-            // streams overlap in time).
-            "transfer", "http3", "multiplexing" -> {
+            // streams overlap in time). The remaining aliases run the same
+            // client logic against different sim configurations:
+            //   transferloss        — random packet loss
+            //   transfercorruption  — random bit-flips (recovery via AEAD AUTH FAIL → drop + retransmit)
+            //   longrtt             — emulated high-latency link
+            //   goodput             — throughput floor under default sim
+            //   crosstraffic        — competing UDP flows on the same link
+            "transfer", "http3", "multiplexing",
+            "transferloss", "transfercorruption", "longrtt", "goodput", "crosstraffic",
+            -> {
                 if (downloads == null) {
                     System.err.println("DOWNLOADS env var required for $testcase")
                     EXIT_FAIL