fix(tanstackstart-react): Use auto.middleware.tanstackstart as middleware trace origin

[nicohrubec]

Should be auto as they are emitted by the SDK.

Closes #19133

[github-actions]

Codecov Results 📊

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Generated by Codecov Action

[github-actions]

Codecov Results 📊

✅ 74 passed | Total: 74 | Pass Rate: 100% | Execution Time: 97ms

All tests are passing successfully.

✅ Patch coverage is 100.00%. Project has 158 uncovered lines.

Files with missing lines (13)

File	Patch %	Lines
middleware.ts	8.06%	⚠️ 57 Missing
wrapFetchWithSentry.ts	8.82%	⚠️ 31 Missing
mute.js	79.10%	⚠️ 14 Missing and 7 partials
sourceMaps.ts	83.33%	⚠️ 19 Missing
index.ts	33.33%	⚠️ 12 Missing
utils.ts	40.00%	⚠️ 9 Missing
index.types.ts	0.00%	⚠️ 5 Missing
index.server.ts	0.00%	⚠️ 4 Missing
index.client.ts	0.00%	⚠️ 2 Missing
index.ts	60.00%	⚠️ 2 Missing
autoInstrumentMiddleware.ts	98.26%	⚠️ 2 Missing
etoa.js	100.00%	⚠️ 1 partials
index.ts	0.00%	⚠️ 1 Missing

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Generated by Codecov Action

[github-actions]

node-overhead report 🧳

Note: This is a synthetic benchmark with a minimal express app and does not necessarily reflect the real-world performance impact in an application.

Scenario	Requests/s	% of Baseline	Prev. Requests/s	Change %
GET Baseline	8,999	-	9,086	-1%
GET With Sentry	1,616	18%	1,653	-2%
GET With Sentry (error only)	5,974	66%	6,094	-2%
POST Baseline	1,135	-	1,166	-3%
POST With Sentry	541	48%	539	+0%
POST With Sentry (error only)	1,000	88%	1,027	-3%
MYSQL Baseline	3,201	-	3,282	-2%
MYSQL With Sentry	422	13%	393	+7%
MYSQL With Sentry (error only)	2,608	81%	2,680	-3%

View base workflow run