fix(executor): isolate log files per task in parallel mode

Previously, all parallel tasks shared the same log file path, making it
difficult to debug individual task execution. This change creates a
separate log file for each task using the naming convention:
codeagent-wrapper-{pid}-{taskName}.log

Changes:
- Add withTaskLogger/taskLoggerFromContext for per-task logger injection
- Modify executeConcurrentWithContext to create independent Logger per task
- Update printTaskStart to display task-specific log paths
- Extract defaultRunCodexTaskFn for proper test hook reset
- Add runCodexTaskFn reset to resetTestHooks()

Test coverage: 93.7%

Generated with swe-agent-bot

Co-Authored-By: swe-agent-bot <agent@swe-agent.ai>

codeagent-wrapper/logger_suffix_test.go

@@ -0,0 +1,80 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func TestLoggerWithSuffixNamingAndIsolation(t *testing.T) {
+	tempDir := setTempDirEnv(t, t.TempDir())
+
+	taskA := "task-1"
+	taskB := "task-2"
+
+	loggerA, err := NewLoggerWithSuffix(taskA)
+	if err != nil {
+		t.Fatalf("NewLoggerWithSuffix(%q) error = %v", taskA, err)
+	}
+	defer loggerA.Close()
+
+	loggerB, err := NewLoggerWithSuffix(taskB)
+	if err != nil {
+		t.Fatalf("NewLoggerWithSuffix(%q) error = %v", taskB, err)
+	}
+	defer loggerB.Close()
+
+	wantA := filepath.Join(tempDir, fmt.Sprintf("%s-%d-%s.log", primaryLogPrefix(), os.Getpid(), taskA))
+	if loggerA.Path() != wantA {
+		t.Fatalf("loggerA path = %q, want %q", loggerA.Path(), wantA)
+	}
+
+	wantB := filepath.Join(tempDir, fmt.Sprintf("%s-%d-%s.log", primaryLogPrefix(), os.Getpid(), taskB))
+	if loggerB.Path() != wantB {
+		t.Fatalf("loggerB path = %q, want %q", loggerB.Path(), wantB)
+	}
+
+	if loggerA.Path() == loggerB.Path() {
+		t.Fatalf("expected different log files, got %q", loggerA.Path())
+	}
+
+	loggerA.Info("from taskA")
+	loggerB.Info("from taskB")
+	loggerA.Flush()
+	loggerB.Flush()
+
+	dataA, err := os.ReadFile(loggerA.Path())
+	if err != nil {
+		t.Fatalf("failed to read loggerA file: %v", err)
+	}
+	dataB, err := os.ReadFile(loggerB.Path())
+	if err != nil {
+		t.Fatalf("failed to read loggerB file: %v", err)
+	}
+
+	if !strings.Contains(string(dataA), "from taskA") {
+		t.Fatalf("loggerA missing its message, got: %q", string(dataA))
+	}
+	if strings.Contains(string(dataA), "from taskB") {
+		t.Fatalf("loggerA contains loggerB message, got: %q", string(dataA))
+	}
+	if !strings.Contains(string(dataB), "from taskB") {
+		t.Fatalf("loggerB missing its message, got: %q", string(dataB))
+	}
+	if strings.Contains(string(dataB), "from taskA") {
+		t.Fatalf("loggerB contains loggerA message, got: %q", string(dataB))
+	}
+}
+
+func TestLoggerWithSuffixReturnsErrorWhenTempDirMissing(t *testing.T) {
+	missingTempDir := filepath.Join(t.TempDir(), "does-not-exist")
+	setTempDirEnv(t, missingTempDir)
+
+	logger, err := NewLoggerWithSuffix("task-err")
+	if err == nil {
+		_ = logger.Close()
+		t.Fatalf("expected error, got nil")
+	}
+}