test(e2e): instrument mock SSE + client stream + fix reachability probe to attribute #90 mode-B (#98)

Adds diagnostics-only instrumentation to attribute the Activation E2E
positive flow's "SSE reply never renders" failure (issue #90 mode B)
between (a) expo/fetch not streaming the SSE response on the Android
release APK, vs (b) a mock-side broadcast bug. Does not change app
behavior or fix the root cause — #90 stays open pending the next CI
run's enriched logs.

- tests/fixtures/mock-opencode-server.ts: per-request logging
  (method/path/status), per-SSE-connection connect/disconnect logging
  with live client count, per-broadcast event-type + client-count
  logging, and a 2s SSE heartbeat comment so client-side silence
  becomes unambiguous.
- src/lib/sdk.ts global.events(): logs on the first successful
  reader.read() that returns data, and when the stream loop ends —
  proves/disproves whether expo/fetch ever delivers a byte.
- scripts/run-e2e-flows.sh: the emulator->mock reachability probe used
  toybox wget/nc, which don't work reliably on the API-28 image.
  Replaced with a probe chain (curl, wget, mksh /dev/tcp, nc, then a
  host-side fallback) that writes a clear PASS/FAIL/UNKNOWN verdict to
  artifacts/diag/probe.txt without blocking the flow.

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

scripts/run-e2e-flows.sh

@@ -22,14 +22,56 @@ for p in 4096 4097 4098 4099; do adb reverse "tcp:$p" "tcp:$p"; done
 adb reverse --list
 
 # Decisive probe: can the EMULATOR actually reach the host mock via 127.0.0.1?
-# If either method prints the health JSON, the network path is good and any flow
-# failure is app-side; if both fail/hang, it's the transport (adb reverse). Both
-# are best-effort — API 28's toybox may or may not ship wget, so nc is a fallback.
-echo "== emulator -> mock reachability probe (127.0.0.1:4096/global/health) ==" | tee "$ROOT/artifacts/diag/probe.txt"
-echo "[wget]" | tee -a "$ROOT/artifacts/diag/probe.txt"
-timeout 15 adb shell 'toybox wget -qO - http://127.0.0.1:4096/global/health' 2>&1 | tee -a "$ROOT/artifacts/diag/probe.txt" || true
-echo "[nc]" | tee -a "$ROOT/artifacts/diag/probe.txt"
-timeout 15 adb shell 'printf "GET /global/health HTTP/1.0\r\n\r\n" | toybox nc 127.0.0.1 4096' 2>&1 | tee -a "$ROOT/artifacts/diag/probe.txt" || true
+# If any in-emulator method prints the health JSON, the network path is good
+# and any flow failure is app-side; if none succeed, attribution falls back to
+# a host-side check + adb reverse state so we at least know the mock is up.
+# `toybox wget`/`nc` don't work reliably on the API-28 image (wget: unknown
+# command; nc connects but the request/response framing is unreliable) — so
+# this tries curl (if present), then mksh's /dev/tcp pseudo-device (a shell
+# builtin, not an external binary, so it survives whatever toybox applets
+# this image did/didn't build), then nc as a last in-emulator attempt, before
+# falling back to a host-side confirmation. This never blocks the flow — the
+# result is recorded and the script continues regardless.
+PROBE_FILE="$ROOT/artifacts/diag/probe.txt"
+probe_result="UNKNOWN"
+
+{
+  echo "== emulator -> mock reachability probe (127.0.0.1:4096/global/health) =="
+} > "$PROBE_FILE"
+
+probe_via() {
+  # $1 = human label for the log, $2 = remote shell command string
+  local label="$1" cmd="$2" out
+  echo "[$label]" | tee -a "$PROBE_FILE"
+  out="$(timeout 10 adb shell "$cmd" 2>&1)"
+  echo "$out" | tee -a "$PROBE_FILE"
+  [[ "$out" == *'"healthy"'* ]]
+}
+
+if probe_via "curl" 'curl -s -m 5 http://127.0.0.1:4096/global/health'; then
+  probe_result="PASS (curl)"
+elif probe_via "toybox-wget" 'toybox wget -qO - http://127.0.0.1:4096/global/health'; then
+  probe_result="PASS (wget)"
+elif probe_via "mksh-devtcp" 'exec 3<>/dev/tcp/127.0.0.1/4096 && printf "GET /global/health HTTP/1.0\r\n\r\n" >&3 && cat <&3'; then
+  probe_result="PASS (/dev/tcp)"
+elif probe_via "nc" 'printf "GET /global/health HTTP/1.0\r\n\r\n" | toybox nc -w 3 127.0.0.1 4096'; then
+  probe_result="PASS (nc)"
+else
+  echo "[fallback: host-side confirmation]" | tee -a "$PROBE_FILE"
+  host_check="$(timeout 5 curl -s http://127.0.0.1:4096/global/health 2>&1 || true)"
+  reverse_list="$(adb reverse --list 2>&1 || true)"
+  {
+    echo "host curl: $host_check"
+    echo "adb reverse --list: $reverse_list"
+  } | tee -a "$PROBE_FILE"
+  if [[ "$host_check" == *'"healthy"'* ]]; then
+    probe_result="UNKNOWN (host mock is up, but no in-emulator method could confirm emulator-side reachability)"
+  else
+    probe_result="FAIL (host mock itself is not responding on 127.0.0.1:4096)"
+  fi
+fi
+
+echo "== probe result: $probe_result ==" | tee -a "$PROBE_FILE"
 
 adb logcat -c || true            # clear, so the captured log is just this run
 

src/lib/sdk.ts

@@ -253,10 +253,19 @@ export function createClient(config: ClientConfig) {
         const decoder = new TextDecoder()
         const parser = new SSEParser()
 
+        let receivedFirstByte = false
         try {
           while (true) {
             const { done, value } = await reader.read()
-            if (done) break
+            if (done) {
+              console.log("[SSE] stream ended")
+              break
+            }
+
+            if (!receivedFirstByte) {
+              receivedFirstByte = true
+              console.log(`[SSE] first byte received (${value?.byteLength ?? 0} bytes)`)
+            }
 
             for (const data of parser.push(decoder.decode(value, { stream: true }))) {
               try {

tests/fixtures/mock-opencode-server.ts

@@ -201,6 +201,7 @@ export function createMockOpencodeServer(opts: MockServerOptions) {
 
   function broadcast(type: string, properties: Record<string, unknown>) {
     const line = `data: ${JSON.stringify({ type, properties })}\n\n`
+    console.log(`[mock-opencode-server] broadcast type=${type} clients=${sseClients.size}`)
     for (const res of sseClients) {
       try {
         res.write(line)
@@ -298,6 +299,12 @@ export function createMockOpencodeServer(opts: MockServerOptions) {
     const path = url.pathname
     const method = req.method || "GET"
 
+    // Per-request logging: proves whether the request ever reached the mock
+    // at all (attributes transport vs. app-side rendering for issue #90).
+    res.on("finish", () => {
+      console.log(`[mock-opencode-server] ${method} ${path} -> ${res.statusCode}`)
+    })
+
     if (failAuth) {
       unauthorized(res)
       return
@@ -387,7 +394,24 @@ export function createMockOpencodeServer(opts: MockServerOptions) {
       })
       res.write(": connected\n\n")
       sseClients.add(res)
-      req.on("close", () => sseClients.delete(res))
+      console.log(`[mock-opencode-server] SSE connect, clients=${sseClients.size}`)
+
+      // Periodic heartbeat comment. If the client never sees even this, the
+      // silence is a transport problem (expo/fetch not streaming), not a
+      // broadcast bug — attributes issue #90 mode B.
+      const heartbeat = setInterval(() => {
+        try {
+          res.write(": ping\n\n")
+        } catch {
+          clearInterval(heartbeat)
+        }
+      }, 2000)
+
+      req.on("close", () => {
+        clearInterval(heartbeat)
+        sseClients.delete(res)
+        console.log(`[mock-opencode-server] SSE disconnect, clients=${sseClients.size}`)
+      })
       return
     }