test(agentcompat): add process supervision harness

Co-authored-by: naiba/CloudCode <hi+cloudcode@nai.ba>

integration/agentcompat/internal/process/cleanup.go

@@ -0,0 +1,46 @@
+//go:build linux
+
+package process
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"path/filepath"
+)
+
+type CleanupRecord struct {
+	Name   string `json:"name"`
+	PID    int    `json:"pid"`
+	Forced bool   `json:"forced"`
+	Error  string `json:"error,omitempty"`
+}
+
+type CleanupReceipt struct {
+	Passed    bool            `json:"passed"`
+	Forced    bool            `json:"forced"`
+	Processes []CleanupRecord `json:"processes"`
+}
+
+func NewCleanupReceipt(records []CleanupRecord) CleanupReceipt {
+	receipt := CleanupReceipt{Passed: true, Processes: append([]CleanupRecord(nil), records...)}
+	for _, record := range records {
+		receipt.Forced = receipt.Forced || record.Forced
+		receipt.Passed = receipt.Passed && record.Error == ""
+	}
+	return receipt
+}
+
+func WriteCleanupReceipt(path string, receipt CleanupReceipt) error {
+	data, err := json.MarshalIndent(receipt, "", "  ")
+	if err != nil {
+		return fmt.Errorf("marshal cleanup receipt: %w", err)
+	}
+	if err := os.MkdirAll(filepath.Dir(path), 0o700); err != nil {
+		return fmt.Errorf("create cleanup receipt directory: %w", err)
+	}
+	if err := os.WriteFile(path, append(data, '\n'), 0o600); err != nil {
+		return fmt.Errorf("write cleanup receipt: %w", err)
+	}
+	return nil
+}