* fix(routing): decode matched params with decodeURIComponent
Vinext's segment-safe normalization preserves encoded delimiters (%2F) for
correct route matching, but the captured param values were left undecoded.
This caused dynamic params to return "a%2Fb" instead of "a/b", diverging
from Next.js which decodes at the route-matcher level.
Add decodeURIComponent pass in trieMatch and matchRoutePattern — the two
route matching entry points — so all downstream consumers (pages, route
handlers, metadata, useParams) receive decoded param values.
Mirrors Next.js: packages/next/src/shared/lib/router/utils/route-matcher.ts L25-27
* test(app-rsc-route-matching): update param decode assertion to match new behavior
* refactor(metadata): share route pattern helpers
Metadata route handling repeated the same dynamic segment normalization and pattern matching in several places. That made the file-convention metadata path harder to review and kept generic routing behavior inside metadata-specific modules.
Move route pattern parsing, matching, and dynamic segment filling into a normal routing module. Reuse it from metadata route build data, file-based metadata, metadata route response matching, and app RSC intercept matching, then consolidate duplicated icon descriptor normalization in the metadata server and shim code.
Add focused route-pattern tests and keep the existing metadata and shim tests covering consumer behavior.
* fix(routing): preserve prototype-named route params
The shared route pattern matcher used a normal object for matched params, unlike the previous metadata and App RSC matchers. A route parameter named __proto__ could mutate the params object's prototype instead of being stored as an own value.
Restore a null-prototype params map and add regression coverage for single and catch-all prototype-named route params.
* fix(routing): preserve literal intercept target segments
Nathan Nguyen