fix(combo): keep nested combos as single units and stop 0-token detail rows

Nested combos (comboA lists comboB, comboC, …) now stay one slot each:
the inner combo always runs as fallback to produce a single answer.
Failed hops are no longer written to Details/usage, and streaming no
longer inserts a 0-token placeholder row.

- chat.js: comboStack cycle detection; nested combos forced to fallback;
  persistUsage="success-only" for combo hops
- combo.js: discardResponse() cancels unused bodies (fusion timeout /
  fallback) so dropped streams fire onStreamComplete; getComboModelsFromData
  keeps nested names and honors enabled=false
- requestDetail.js: tokensForDetail() canonicalizes Claude/Gemini usage;
  shouldPersistRequestDetail() skips streaming-start and non-success hops
- streamingHandler.js: drop the 0-token streaming placeholder write
- RequestDetailsTab.js: read Gemini/Claude token names; show "streaming"
  status in amber
- tests: add combo-nested.test.js (13 cases)
- gitignore: ignore local .vitest/ artifacts

Co-authored-by: CommandCodeBot <noreply@commandcode.ai>

open-sse/handlers/chatCore/streamingHandler.js

@@ -13,6 +13,8 @@ import {
 	extractRequestConfig,
 	saveUsageStats,
 	formatDoneLine,
+	tokensForDetail,
+	shouldPersistRequestDetail,
 } from "./requestDetail.js";
 import { streamStatusForContent } from "../../utils/streamErrorPatterns.js";
 import { saveRequestDetail } from "@/lib/usageDb.js";
@@ -60,7 +62,7 @@ function buildTransformStream({ provider, sourceFormat, targetFormat, userAgent,
 /**
  * Handle streaming response — pipe provider SSE through transform stream to client.
  */
-export async function handleStreamingResponse({ providerResponse, provider, model, sourceFormat, targetFormat, userAgent, body, stream, translatedBody, finalBody, requestStartTime, connectionId, apiKey, clientRawRequest, onRequestSuccess, reqLogger, toolNameMap, customToolNames, streamController, onStreamComplete, streamDetailId, pxpipe, reqTag, log, credentials }) {
+export async function handleStreamingResponse({ providerResponse, provider, model, sourceFormat, targetFormat, userAgent, body, stream, translatedBody, finalBody, requestStartTime, connectionId, apiKey, clientRawRequest, onRequestSuccess, reqLogger, toolNameMap, customToolNames, streamController, onStreamComplete, pxpipe, reqTag, log, credentials }) {
   if (onRequestSuccess) {
     Promise.resolve()
       .then(onRequestSuccess)
@@ -145,35 +147,6 @@ export async function handleStreamingResponse({ providerResponse, provider, mode
 		stallTimeoutMs,
 	);
 
-	saveRequestDetail(
-		buildRequestDetail(
-			{
-				provider,
-				model,
-				connectionId,
-				apiKey,
-				latency: { ttft: 0, total: Date.now() - requestStartTime },
-				tokens: { prompt_tokens: 0, completion_tokens: 0 },
-				request: extractRequestConfig(body, stream),
-				providerRequest: finalBody || translatedBody || null,
-				providerResponse: "[Streaming - raw response not captured]",
-				response: {
-					content: "[Streaming in progress...]",
-					thinking: null,
-					type: "streaming",
-				},
-				pxpipe,
-				status: "success",
-			},
-			{ id: streamDetailId },
-		),
-	).catch((err) => {
-		console.error(
-			"[RequestDetail] Failed to save streaming request:",
-			err.message,
-		);
-	});
-
 	return {
 		success: true,
 		response: new Response(transformedBody, { headers: SSE_HEADERS }),
@@ -198,6 +171,7 @@ export function buildOnStreamComplete({
 	reqTag,
 	log,
 	streamErrorPatterns,
+	persistUsage = "all",
 }) {
 	const streamDetailId = `${Date.now()}-${Math.random().toString(36).slice(2, 11)}`;
 
@@ -210,37 +184,39 @@ export function buildOnStreamComplete({
 		const safeThinking = contentObj?.thinking || null;
 		const rawProviderText = typeof contentObj?.rawProviderText === "string" ? contentObj.rawProviderText : "";
 
-		saveRequestDetail(
-			buildRequestDetail(
-				{
-					provider,
-					model,
-					connectionId,
-					apiKey,
-					latency,
-					tokens: usage || { prompt_tokens: 0, completion_tokens: 0 },
-					request: extractRequestConfig(body, stream),
-					providerRequest: finalBody || translatedBody || null,
-					providerResponse: rawProviderText || safeContent,
-					response: {
-						content: safeContent,
-						thinking: safeThinking,
-						type: "streaming",
+		if (shouldPersistRequestDetail(persistUsage, "success")) {
+			saveRequestDetail(
+				buildRequestDetail(
+					{
+						provider,
+						model,
+						connectionId,
+						apiKey,
+						latency,
+						tokens: tokensForDetail(usage),
+						request: extractRequestConfig(body, stream),
+						providerRequest: finalBody || translatedBody || null,
+						providerResponse: rawProviderText || safeContent,
+						response: {
+							content: safeContent,
+							thinking: safeThinking,
+							type: "streaming",
+						},
+						pxpipe,
+						status: streamStatusForContent(
+							streamErrorPatterns?.[provider],
+							safeContent,
+						),
 					},
-					pxpipe,
-					status: streamStatusForContent(
-						streamErrorPatterns?.[provider],
-						safeContent,
-					),
-				},
-				{ id: streamDetailId },
-			),
-		).catch((err) => {
-			console.error(
-				"[RequestDetail] Failed to update streaming content:",
-				err.message,
-			);
-		});
+					{ id: streamDetailId },
+				),
+			).catch((err) => {
+				console.error(
+					"[RequestDetail] Failed to update streaming content:",
+					err.message,
+				);
+			});
+		}
 
 		// Persist stream usage to DB (no console line; the "📊 done" line below is authoritative)
 		saveUsageStats({