fix(agent): stabilize review item fingerprints

internal/agent/agent.go

@@ -775,7 +775,11 @@ func (a *Agent) reviewMode() string {
 }
 
 func reviewItemFingerprint(mode string, d model.Diff) string {
-	sum := sha256.Sum256([]byte(mode + "\x00" + d.OldPath + "\x00" + d.NewPath + "\x00" + d.Diff))
+	// The patch splitter can leave extra line endings on the final file in a
+	// multi-file patch. Unified diff content lines always carry a marker, so
+	// trimming CR/LF here removes only that position-dependent delimiter.
+	diffText := strings.TrimRight(d.Diff, "\r\n")
+	sum := sha256.Sum256([]byte(mode + "\x00" + d.OldPath + "\x00" + d.NewPath + "\x00" + diffText))
 	return fmt.Sprintf("%x", sum)
 }
 

internal/agent/agent_test.go

@@ -559,6 +559,35 @@ func TestFilterLargeDiffs_ZeroMaxTokens(t *testing.T) {
 	}
 }
 
+func TestReviewItemFingerprintIgnoresTrailingLineEndings(t *testing.T) {
+	base := model.Diff{
+		OldPath: "main.go",
+		NewPath: "main.go",
+		Diff:    "@@ -1 +1 @@\n-old\n+new",
+	}
+	want := reviewItemFingerprint(session.ReviewModeRange, base)
+
+	for name, suffix := range map[string]string{
+		"lf":               "\n",
+		"crlf":             "\r\n",
+		"extra blank line": "\n\n",
+	} {
+		t.Run(name, func(t *testing.T) {
+			d := base
+			d.Diff += suffix
+			if got := reviewItemFingerprint(session.ReviewModeRange, d); got != want {
+				t.Errorf("fingerprint = %q, want %q", got, want)
+			}
+		})
+	}
+
+	withContextLine := base
+	withContextLine.Diff += "\n "
+	if got := reviewItemFingerprint(session.ReviewModeRange, withContextLine); got == want {
+		t.Error("fingerprint ignored a real trailing context line")
+	}
+}
+
 func TestApplyResumeReusesCompletedItemsAcrossModels(t *testing.T) {
 	diffs := []model.Diff{
 		{OldPath: "a.go", NewPath: "a.go", Diff: "+a", Insertions: 1},