fix: harden operations and configuration recovery

internal/apt/apt.go

@@ -2,7 +2,6 @@
 package apt
 
 import (
-	"bufio"
 	"context"
 	"errors"
 	"fmt"
@@ -15,6 +14,7 @@ import (
 	"sort"
 	"strings"
 
+	"proxyctl/internal/execsafe"
 	"proxyctl/internal/profile"
 	"proxyctl/internal/securefs"
 	"proxyctl/internal/target"
@@ -77,7 +77,7 @@ type Runner interface {
 
 type systemRunner struct{}
 
-func (systemRunner) LookPath(name string) (string, error) { return exec.LookPath(name) }
+func (systemRunner) LookPath(name string) (string, error) { return execsafe.LookPath(name) }
 func (systemRunner) Output(ctx context.Context, name string, args ...string) ([]byte, error) {
 	return exec.CommandContext(ctx, name, args...).Output()
 }
@@ -435,9 +435,8 @@ func aptQuote(value string) string {
 
 func parseConfiguration(data []byte) map[string]string {
 	settings := make(map[string]string)
-	scanner := bufio.NewScanner(strings.NewReader(string(data)))
-	for scanner.Scan() {
-		line := strings.TrimSpace(scanner.Text())
+	for _, raw := range strings.Split(string(data), "\n") {
+		line := strings.TrimSpace(raw)
 		if line == "" || strings.HasPrefix(line, "//") || strings.HasPrefix(line, "#") {
 			continue
 		}