fix(nextjs): Set parameterized transaction name for non-transaction events

[chargome]

Calls to Sentry.captureException() inside a Next.js App Router route handler, lead to unparameterized transaction names

• This happens because non-transaction events read their transaction from the isolation scope's transactionName, which is set to the raw URL by httpServerIntegration. On turbopack, the webpack wrapping loader doesn't run, so wrapRouteHandlerWithSentry (which sets the parameterized name on the current scope) is never called.
• The fix updates handleOnSpanStart to also set the parameterized route on the isolation scope when hoisting the next.route attribute to the root span. This ensures manually captured events get the parameterized route regardless of bundler.
• Adds E2E tests for route handler errors (throw), captureException, and captureMessage with parameterized routes in the nextjs-16 test app.

closes #19312

[github-actions]

Codecov Results 📊

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Generated by Codecov Action

[github-actions]

Codecov Results 📊

✅ Patch coverage is 100.00%. Project has 14 uncovered lines.
✅ Project coverage is 83.13%. Comparing base (base) to head (head).

Files with missing lines (2)

File	Patch %	Lines
mute.js	79.10%	⚠️ 14 Missing and 7 partials
etoa.js	100.00%	⚠️ 1 partials

Coverage diff

@@            Coverage Diff             @@
##          main       #PR       +/-##
==========================================
+ Coverage    60.31%    83.13%   +22.82%
==========================================
  Files          756         2      -754
  Lines        41847        83    -41764
  Branches      7996        57     -7939
==========================================
+ Hits         25248        69    -25179
- Misses       16599        14    -16585
- Partials        82         8       -74

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[andreiborza]

LGTM

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

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[cursor]

Test uses conditional instead of separate test cases

Low Severity

The test at line 69 uses if (process.env.TEST_ENV === 'development') to conditionally run assertions for nextjs context and mechanism. Per the project review rules, conditionals within a single test case are discouraged — the recommendation is to split the test into separate test cases for each environment path. This ensures both paths are always visible in test results and avoids silently skipping assertions.

 

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