chore: update progress for US-085

Author: NathanFlurry

prd.json

@@ -2020,7 +2020,7 @@
         "Tests pass"
       ],
       "priority": 120,
-      "passes": false,
+      "passes": true,
       "notes": "Phase 3 of terminal-e2e-testing.md spec. Known risk: cross-runtime stdout routing through proc_spawn \u2192 kernel \u2192 PTY has known issues \u2014 if tests fail, fix is in spawn/stdio wiring, not test infrastructure. Adversarial review added: ^C during cross-runtime spawn \u2014 signal must reach correct process and shell must survive."
     },
     {

progress.txt

@@ -1721,3 +1721,22 @@ PRD: ralph/kernel-hardening (46 stories)
   - PtyManager constructor takes optional onSignal callback — pass a throwing function in tests to verify resilience
   - setForegroundPgid requires a non-zero pgid for signal delivery to trigger
 ---
+
+## 2026-03-18 - US-085
+- What was implemented: Cross-runtime terminal tests and kernel fix for cross-runtime child process output routing
+  - Fixed kernel spawnInternal: cross-runtime children now inherit parent's onStdout/onStderr callbacks when stdout is not piped, enabling child output to reach exec() collector
+  - Fixed kernel spawnInternal: parent driver's PID set now includes cross-runtime child PIDs, allowing parent to waitpid on children spawned via different runtime drivers
+  - Test 1: `node -e "console.log(42)"` from brush-shell → "42" appears on screen via TerminalHarness
+  - Test 2: `^C` during `node -e "setTimeout(...)"` → shell survives, prompt returns, can run more commands
+  - Test 3: `python3 -c "print(99)"` from brush-shell → "99" appears (gated on pyodide ESM import availability)
+- Files changed:
+  - packages/kernel/src/kernel.ts — added cross-runtime PID ownership sharing + parent stdout/stderr callback inheritance
+  - packages/secure-exec/tests/kernel/cross-runtime-terminal.test.ts — NEW: 3 cross-runtime terminal tests
+  - prd.json — marked US-085 (P120) as passes: true
+- **Learnings for future iterations:**
+  - Root cause of cross-runtime EPERM: kernel assertOwns(pid) check rejected parent driver accessing child PID owned by a different driver — fix: register child PID in parent's driver PID set too
+  - Root cause of empty stdout: child process got its own isolated stdoutBuf instead of inheriting parent's callback — fix: look up parent's ProcessEntry.driverProcess.onStdout
+  - kernel.exec() always routes through `sh -c` (brush-shell) — ALL cross-runtime commands go through WasmVM proc_spawn
+  - pyodide `require.resolve()` succeeds but `await import('pyodide')` fails — use dynamic import check for accurate gating
+  - Cross-runtime pipe tests (echo | node) still fail — separate issue from output routing (pipe EOF/close semantics)
+---