internal/opencode: runner (idle/hard timeout, process-group kill, resume-fallback) + verdict/json parsing

internal/opencode/pgid_linux.go

@@ -0,0 +1,23 @@
+//go:build linux
+
+package opencode
+
+import (
+	"os/exec"
+	"syscall"
+)
+
+func sysProcAttr(proc *exec.Cmd) {
+	proc.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
+}
+
+// killProcGroup убивает всю process-group по лидеру pid (SIGKILL дочерним и
+// SIGTERM лидеру). Игнорирует ошибки: weakest-effort teardown.
+func killProcGroup(pid int) {
+	pgid, err := syscall.Getpgid(pid)
+	if err != nil {
+		return
+	}
+	_ = syscall.Kill(-pgid, syscall.SIGKILL)
+	_ = syscall.Kill(pid, syscall.SIGKILL)
+}