feat(tanstackstart-react): Auto-instrument request middleware

[nicohrubec]

Follow up to #18844

Extending auto-instrumentation to non-global server request middleware.

TSS request middleware docs

Closes #18846

[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	8,634	-	9,023	-4%
GET With Sentry	1,693	20%	1,693	-
GET With Sentry (error only)	5,943	69%	6,130	-3%
POST Baseline	1,181	-	1,201	-2%
POST With Sentry	570	48%	585	-3%
POST With Sentry (error only)	1,008	85%	1,056	-5%
MYSQL Baseline	3,210	-	3,337	-4%
MYSQL With Sentry	451	14%	474	-5%
MYSQL With Sentry (error only)	2,633	82%	2,703	-3%

View base workflow run