fix(ui): correct usage range totals and muted styles

src/infra/session-cost-usage.test.ts

@@ -371,4 +371,57 @@ describe("session cost usage", () => {
       }
     }
   });
+
+  it("preserves totals and cumulative values when downsampling timeseries", async () => {
+    const root = await fs.mkdtemp(path.join(os.tmpdir(), "openclaw-timeseries-downsample-"));
+    const sessionsDir = path.join(root, "agents", "main", "sessions");
+    await fs.mkdir(sessionsDir, { recursive: true });
+    const sessionFile = path.join(sessionsDir, "sess-downsample.jsonl");
+
+    const entries = Array.from({ length: 10 }, (_, i) => {
+      const idx = i + 1;
+      return {
+        type: "message",
+        timestamp: new Date(Date.UTC(2026, 1, 12, 10, idx, 0)).toISOString(),
+        message: {
+          role: "assistant",
+          provider: "openai",
+          model: "gpt-5.2",
+          usage: {
+            input: idx,
+            output: idx * 2,
+            cacheRead: 0,
+            cacheWrite: 0,
+            totalTokens: idx * 3,
+            cost: { total: idx * 0.001 },
+          },
+        },
+      };
+    });
+
+    await fs.writeFile(
+      sessionFile,
+      entries.map((entry) => JSON.stringify(entry)).join("\n"),
+      "utf-8",
+    );
+
+    const timeseries = await loadSessionUsageTimeSeries({
+      sessionFile,
+      maxPoints: 3,
+    });
+
+    expect(timeseries).toBeTruthy();
+    expect(timeseries?.points.length).toBe(3);
+
+    const points = timeseries?.points ?? [];
+    const totalTokens = points.reduce((sum, point) => sum + point.totalTokens, 0);
+    const totalCost = points.reduce((sum, point) => sum + point.cost, 0);
+    const lastPoint = points[points.length - 1];
+
+    // Full-series totals: sum(1..10)*3 = 165 tokens, sum(1..10)*0.001 = 0.055 cost.
+    expect(totalTokens).toBe(165);
+    expect(totalCost).toBeCloseTo(0.055, 8);
+    expect(lastPoint?.cumulativeTokens).toBe(165);
+    expect(lastPoint?.cumulativeCost).toBeCloseTo(0.055, 8);
+  });
 });