fix(process): stop a stream error from crashing the main process

Same class as the stdin EPIPE finding, two instances further on: stdout
and stderr had data listeners and no error listeners, and an unhandled
error on a stream is an uncaught exception.

Scoped to runProcess, which owns the child outright. spawnProcess hands
the streams to its caller, and a blanket handler there defeats callers
that track and remove their own listeners -- the SSH ProxyCommand
transport does exactly that, and its cleanup test caught the attempt.
Documented on spawnProcess so the boundary is explicit rather than
inferred.

src/main/windows/windows-process-table.test.ts

@@ -191,8 +191,10 @@ describe('wedge cooldown', () => {
     await vi.advanceTimersByTimeAsync(10_000)
 
     // The recovered reader must answer, not report a wedge left by a dead timer.
-    getAllProcesses.mockImplementation((cb: (rows: unknown) => void) => cb(NATIVE))
-    resetWindowsProcessTableForTests()
+    __setWindowsProcessTreeLoaderForTests(() => ({
+      ProcessDataFlag: { None: 0, Memory: 1, CommandLine: 2 },
+      getAllProcesses: (cb: (rows: typeof NATIVE | undefined) => void) => cb(NATIVE)
+    }))
     await expect(readWindowsProcessTableFresh()).resolves.toHaveLength(NATIVE.length)
   })
 })

src/shared/child-process/run-process.ts

@@ -248,13 +248,6 @@ export function runProcess(spec: ProcessSpec): Promise<ProcessResult> {
     // Why close rather than leave open: a child that reads stdin (a hook
     // draining its payload, a CLI probing for a TTY) otherwise blocks until the
     // timeout instead of seeing EOF immediately.
-    // Why an error listener and not just end(): a child that exits without
-    // reading makes the queued write fail with EPIPE, and an unhandled error on
-    // a stream is an uncaught exception -- which takes the whole main process
-    // down. The child's own error listener does not cover this stream. The
-    // exit code already carries the outcome, so failing to deliver stdin is
-    // not separately interesting.
-    child.stdin?.on('error', () => {})
     child.stdin?.end(spec.input)
   })
 }