feat(router-generator): support higher-order wrappers around createFileRoute

[dhleong]

The route-file transform previously required the exported Route binding to be exactly createFileRoute('/path')({...}), so a route wrapped by a higher-order handler (e.g. wrap('x')(createFileRoute('/path')({...}))) was silently left untouched — no route-id injection, no import management.

This change will recursively locate the single nested createFileRoute(path)(options) call within the exported Route init, regardless of any wrapping calls. The wrapper stays opaque to the generator; only the inner constructor call is rewritten. Malformed wrapped routes now surface the same helpful error.

This is proposed as a first step toward unblocking #7619

Summary by CodeRabbit

• New Features

  • Route generation now works with route definitions wrapped in higher-order expressions, preserving wrapper code while updating the route call inside.
  • Lazy route handling is now supported even when the route constructor appears within nested wrappers.

• Bug Fixes

  • Improved error detection for malformed wrapped route definitions.
  • Added clearer failures when a wrapped route call is missing required options or contains multiple route constructor calls.

[coderabbitai]

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ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 85054867-4ada-442a-8296-4022044ab7bd

📥 Commits

Reviewing files that changed from the base of the PR and between a3e24c3 and 6620e35.

📒 Files selected for processing (2)

• packages/router-generator/src/transform/transform.ts
• packages/router-generator/tests/transform.test.ts

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📝 Walkthrough

Walkthrough

The route-export analyzer in transform.ts now recursively searches wrapper expressions for nested createFileRoute/createLazyFileRoute calls instead of requiring direct initialization. New helper functions replace the prior direct-call detection, and new tests validate wrapped route id injection, lazy swapping, multiple wrappers, and error cases.

Changes

Higher-order Route Wrapper Support

Layer / File(s)	Summary
Route-constructor detection helpers packages/router-generator/src/transform/transform.ts	getRouteConstructorInit accepts wider node types; new findRouteConstructorInits and containsRouteConstructorCall recursively walk call-expression trees, replacing removed isDirectRouteConstructorCall.
Exported route call discovery packages/router-generator/src/transform/transform.ts	findExportedRouteCalls traverses the full initializer expression to find nested route-constructor calls and distinguishes malformed calls from unsupported/absent ones using the new helpers.
Wrapper transform tests packages/router-generator/tests/transform.test.ts	New "higher-order route wrappers" test suite covers route id injection, lazy swapping, nested wrappers, and error cases for missing options or multiple constructor calls.

Estimated code review effort: 3 (Moderate) | ~25 minutes

Sequence Diagram(s)

sequenceDiagram
  participant Transform as transform()
  participant Finder as findExportedRouteCalls
  participant Walker as findRouteConstructorInits
  participant Checker as containsRouteConstructorCall

  Transform->>Finder: analyze exported binding initializer
  Finder->>Walker: traverse expression tree for route constructor inits
  Walker-->>Finder: matched inits (createFileRoute/createLazyFileRoute)
  alt no inits found
    Finder->>Checker: check for any constructor call in tree
    Checker-->>Finder: hasMalformedRouteCall or unsupported
  end
  Finder-->>Transform: calls list or error state

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🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the main change: supporting higher-order wrappers around createFileRoute.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

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