[seongwon030]

Closes #25638

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location.pathname is percent-encoded, but React Router decodes the pathname before matching (decodePath), so RouteMatch.pathname and pathnameBase are decoded. The React Router instrumentation compared the two with plain string equality, so a route like /clubs/:clubId visited as /clubs/%ED%95%9C%EA%B8%80 never matched and the transaction fell back to the raw URL with source url. Every non-ASCII parameter value became its own transaction name. Descendant routes (<Routes> nested under a /* route) produced the raw URL with source route.

This adds decodePathname, the same segment-wise algorithm as React Router's decodePath, and applies it to both sides of the comparison in getNormalizedName and of the pathnameBase stripping for descendant routes. Decoding both sides keeps percent-encoded basenames and older 6.x routers working: before 6.22.1 matchRoutes matched against the raw pathname or used decodeURI, so there the branch pathname is the side that is still encoded. A value that still looks percent-encoded after one decode (a literal %41) is decoded once more; such values were not parameterized before either.

Validation (in packages/react):

• vitest run on the React Router suites (react-router, reactrouterv6, reactrouter-descendant-routes, reactrouter-cross-usage, reactrouter-compat-utils/*): 276 tests passed, including the new ones
• The new decodePathname, getNormalizedName, rebuildRoutePathFromAllRoutes, v7 pageload/navigation and v6 descendant-route tests fail without the fix
• pnpm run lint clean; oxfmt --check passed on the changed files
• Browser integration tests (Playwright) were not run