[Impl] Make text overview truncation Unicode-safe

internal/engine/engine_test.go

@@ -9,6 +9,7 @@ import (
 	"strings"
 	"testing"
 	"time"
+	"unicode/utf8"
 
 	"github.com/luoyuctl/agenttrace/internal/i18n"
 )
@@ -1892,6 +1893,47 @@ func TestReportOverviewTextShowsIncidentAndAuthorityCues(t *testing.T) {
 	}
 }
 
+func TestReportOverviewTextTruncatesUnicodeSafely(t *testing.T) {
+	longName := "x" + strings.Repeat("项目", 24) + "-异常会话"
+	longTool := "x" + strings.Repeat("工具", 32)
+	sessions := []Session{{
+		Name:      longName,
+		Health:    45,
+		Anomalies: []Anomaly{{Type: "hanging", Severity: SeverityHigh}},
+		Metrics: Metrics{
+			SourceTool:       "codex_cli",
+			ModelUsed:        "gpt-5.1",
+			AssistantTurns:   3,
+			DurationSec:      180,
+			GapsSec:          []float64{90},
+			ToolCallsOK:      1,
+			ToolCallsFail:    2,
+			ToolUsage:        map[string]int{longTool: 3},
+			ToolAuthority:    map[string]int{ToolAuthorityTestOrBuild: 1},
+			HighestAuthority: ToolAuthorityTestOrBuild,
+		},
+	}}
+
+	out := ReportOverview(ComputeOverview(sessions), sessions)
+	if !utf8.ValidString(out) {
+		t.Fatalf("text overview should stay valid UTF-8 after truncation:\n%x", out)
+	}
+	for _, want := range []string{
+		"Incident timeline",
+		"Touched surface",
+		"Tool authority",
+		"Recent Anomalies",
+		"...",
+	} {
+		if !strings.Contains(out, want) {
+			t.Fatalf("text overview missing %q:\n%s", want, out)
+		}
+	}
+	if strings.ContainsRune(out, '\uFFFD') {
+		t.Fatalf("text overview contains replacement characters after truncation:\n%s", out)
+	}
+}
+
 func TestTextCellCollapsesWhitespaceAndTruncatesUTF8(t *testing.T) {
 	got := textCell("命令\n执行  失败 😅", 8)
 	if got != "命令 执行..." {

internal/engine/incident_timeline.go

@@ -155,8 +155,5 @@ func incidentSafeName(value string) string {
 	if fields := strings.Fields(value); len(fields) > 0 {
 		value = fields[0]
 	}
-	if len(value) > 48 {
-		value = value[:48]
-	}
-	return value
+	return truncateTextRunes(value, 48, "")
 }

internal/engine/report.go

@@ -6,6 +6,7 @@ import (
 	"html"
 	"sort"
 	"strings"
+	"unicode/utf8"
 
 	"github.com/luoyuctl/agenttrace/internal/i18n"
 )
@@ -1216,11 +1217,7 @@ func ReportOverview(ov Overview, sessions []Session) string {
 		}
 		for i := 0; i < limit; i++ {
 			a := ov.AnomaliesTop[i]
-			name := a.Session
-			if len(name) > 30 {
-				name = name[:30]
-			}
-			wf("    ⚠️  %-30s %s", name, reportAnomalyTypeLabel(a.Type))
+			wf("    ⚠️  %-30s %s", textCell(a.Session, 30), reportAnomalyTypeLabel(a.Type))
 		}
 	}
 	w("")
@@ -1238,9 +1235,25 @@ func textAuthorityCounts(items []authorityCount) string {
 
 func textCell(value string, limit int) string {
 	value = strings.Join(strings.Fields(value), " ")
-	runes := []rune(value)
-	if limit > 3 && len(runes) > limit {
-		return string(runes[:limit-3]) + "..."
+	if limit > 3 {
+		return truncateTextRunes(value, limit, "...")
 	}
 	return value
 }
+
+func truncateTextRunes(value string, limit int, suffix string) string {
+	if limit <= 0 {
+		return ""
+	}
+	if utf8.RuneCountInString(value) <= limit {
+		return value
+	}
+	cut := limit
+	if suffixRunes := utf8.RuneCountInString(suffix); suffix != "" && suffixRunes < limit {
+		cut = limit - suffixRunes
+	} else {
+		suffix = ""
+	}
+	runes := []rune(value)
+	return string(runes[:cut]) + suffix
+}