docs: clarify tRPC frontend entrypoints

[louzhedong]

Summary

Update the tRPC usage docs to better reflect the current frontend entrypoints.

Why

The docs still lean on an older utils/api.ts framing, which can be confusing when comparing Pages Router and App Router setup.

What changed

• Clarified that utils/api.ts is the Pages Router entry point
• Pointed App Router readers to src/trpc/react.tsx
• Kept the rest of the tRPC walkthrough intact

Verification

• Cross-checked the docs against the current scaffold structure

[changeset-bot]

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Latest commit: 3a3c32c

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Project	Deployment	Actions	Updated (UTC)
create-t3-app	Ready	Preview, Comment	Jun 7, 2026 2:06pm