docs(js): Review and update TanStack Start React quick start guide

[inventarSarah]

DESCRIBE YOUR PR

Reviewed the existing TanStack Start React quick start guide and made some updates:

• improved structures by adding subheadings
• rewrote some explanations to be more concise and in line with similar content in other QS guides
• updated verification code snippets (tested with the latest version of the framework)

Closes: #14878

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  Thanks in advance for your help!

PRE-MERGE CHECKLIST

Make sure you've checked the following before merging your changes:

• Checked Vercel preview for correctness, including links
• PR was reviewed and approved by any necessary SMEs (subject matter experts)
• PR was reviewed and approved by a member of the Sentry docs team

EXTRA RESOURCES

• Sentry Docs contributor guide

---

Note

Rewrites and restructures the TanStack Start React quick start with clearer client/server setup, SSR and server instrumentation, updated tracing example, and improved verification and links.

• Docs — TanStack Start React guide (index.mdx):
  • Restructure: Clearer intro and step-based flow; added subheadings and optional sections.
  • Client/Server Setup: Separate client and server init; clarified config and options.
  • Performance/SSR: Added wrapCreateRootRouteWithSentry and wrapStreamHandlerWithSentry; grouped under performance option.
  • Server Functions: Added global middleware via sentryGlobalServerMiddlewareHandler.
  • Error Handling: Guidance for error boundaries via withErrorBoundary and capturing errorComponent errors with captureException; note on automatic client capture.
  • Tracing Example: Replaced API route with server route src/routes/sentry-example.ts (/sentry-example); updated fetch path and example code.
  • Verification/Extras: Added tunneling section; refined verification steps; expanded Next Steps with product features and troubleshooting links.
• Docs — Config (config.yml): Updated description to a more comprehensive summary.

^{Written by Cursor Bugbot for commit 2ba052c. This will update automatically on new commits. Configure here.}

[vercel]

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Project	Deployment	Preview	Comments	Updated (UTC)
develop-docs	Ready	Preview	Comment	Sep 30, 2025 11:04am
sentry-docs	Canceled			Sep 30, 2025 11:04am

[codecov]

Bundle Report

Changes will decrease total bundle size by 87.04kB (-0.37%) ⬇️. This is within the configured threshold ✅

Detailed changes

Bundle name	Size	Change
sentry-docs-client-array-push	10.13MB	-6 bytes (-0.0%) ⬇️
sentry-docs-server-cjs	12.81MB	-87.03kB (-0.67%) ⬇️

Affected Assets, Files, and Routes:

view changes for bundle: sentry-docs-server-cjs

Assets Changed:

Asset Name	Size Change	Total Size	Change (%)
1729.js	-3 bytes	1.78MB	-0.0%
../instrumentation.js	-3 bytes	1.1MB	-0.0%
9523.js	-3 bytes	1.08MB	-0.0%
../app/[[...path]]/page.js.nft.json	-29.01kB	809.32kB	-3.46%
../app/platform-redirect/page.js.nft.json	-29.01kB	809.23kB	-3.46%
../app/sitemap.xml/route.js.nft.json	-29.01kB	806.46kB	-3.47%

view changes for bundle: sentry-docs-client-array-push

Assets Changed:

Asset Name	Size Change	Total Size	Change (%)
static/chunks/pages/_app-*.js	-3 bytes	882.71kB	-0.0%
static/chunks/8321-*.js	-3 bytes	425.87kB	-0.0%
server/middleware-*.js	-6.46kB	1.0kB	-86.59%
server/middleware-*.js	6.46kB	7.46kB	645.5% ⚠️
static/VWTOS_1G-*.js (New)	684 bytes	684 bytes	100.0% 🚀
static/VWTOS_1G-*.js (New)	77 bytes	77 bytes	100.0% 🚀
static/RCHm5byAG3GyOD7SqB5EU/_buildManifest.js (Deleted)	-684 bytes	0 bytes	-100.0% 🗑️
static/RCHm5byAG3GyOD7SqB5EU/_ssgManifest.js (Deleted)	-77 bytes	0 bytes	-100.0% 🗑️

[chargome]

I think we should not name this client side if we're talking about server side right below, wdyt? Maybe something more general

[inventarSarah]

Updated to "Capturing Errors in Error Boundaries and Components (Optional)" -- almost identical to the original title.
But please let me know if you have a more general idea :)

[coolguyzone]

Thanks, looks good! 😊