Report context window usage for Paseo Agent

toAgentUsage dropped SessionStats.contextUsage, leaving the context-window
indicator blank on every Paseo Agent session. Mirror the Pi provider's
mapping into contextWindowMaxTokens/contextWindowUsedTokens.

packages/server/src/server/agent/providers/paseo-agent/agent.test.ts

@@ -108,6 +108,7 @@ class FakeInProcessPiSession {
       totalMessages: 2,
       tokens: { input: 3, output: 5, cacheRead: 2, cacheWrite: 0, total: 10 },
       cost: 0.01,
+      contextUsage: { contextWindow: 200000, tokens: 1234, percentage: 0.6 },
     };
   }
 
@@ -452,7 +453,14 @@ describe("PaseoAgentSession runtime events", () => {
     await expect(resultPromise).resolves.toEqual({
       sessionId: "pi-session-1",
       finalText: "done",
-      usage: { inputTokens: 3, cachedInputTokens: 2, outputTokens: 5, totalCostUsd: 0.01 },
+      usage: {
+        inputTokens: 3,
+        cachedInputTokens: 2,
+        outputTokens: 5,
+        totalCostUsd: 0.01,
+        contextWindowMaxTokens: 200000,
+        contextWindowUsedTokens: 1234,
+      },
       timeline: [
         { type: "reasoning", text: "thinking" },
         {

packages/server/src/server/agent/providers/paseo-agent/event-mapping.ts

@@ -327,10 +327,26 @@ export function toAgentUsage(stats: SessionStats): AgentUsage | undefined {
   const cachedInputTokens = stats.tokens.cacheRead;
   const outputTokens = stats.tokens.output;
   const totalCostUsd = stats.cost;
-  if (inputTokens === 0 && cachedInputTokens === 0 && outputTokens === 0 && totalCostUsd === 0) {
+  const contextWindowMaxTokens = stats.contextUsage?.contextWindow ?? undefined;
+  const contextWindowUsedTokens = stats.contextUsage?.tokens ?? undefined;
+  if (
+    inputTokens === 0 &&
+    cachedInputTokens === 0 &&
+    outputTokens === 0 &&
+    totalCostUsd === 0 &&
+    contextWindowMaxTokens === undefined &&
+    contextWindowUsedTokens === undefined
+  ) {
     return undefined;
   }
-  return { inputTokens, cachedInputTokens, outputTokens, totalCostUsd };
+  return {
+    inputTokens,
+    cachedInputTokens,
+    outputTokens,
+    totalCostUsd,
+    ...(typeof contextWindowMaxTokens === "number" ? { contextWindowMaxTokens } : {}),
+    ...(typeof contextWindowUsedTokens === "number" ? { contextWindowUsedTokens } : {}),
+  };
 }
 
 const PiTextContentSchema = z.object({ type: z.literal("text"), text: z.string() });