fix: stop emitting the unused old field on registry tokens

[simulieren]

Closes #119.

What changes

• RegistryGenerator#sanitizeTokens keeps type, val and end only. old was matchit's copy of the whole route pattern, repeated once per token, and nothing on the client reads it: createURL uses type/val/end, TuyauRouter matches on pattern.
• AdonisEndpoint.tokens is typed with a new exported ClientRouteToken, which is ClientRouteMatchItTokens with old optional.
• Tuyau#createUrlBuilder builds the ClientRouteJSON[] it hands to the http-server URL builder explicitly and asserts the token type, since that builder's type still declares old.
• Changeset: patch for @tuyau/core.

Backward compatibility

• A registry generated by an earlier version (tokens with old) still type-checks against the new AdonisEndpoint and still works at runtime, because old is optional and ignored.
• A registry generated by this version works with the http-server URL builder unchanged; createURL never touched old.
• The generator and the client ship in the same package, so a user never runs a new registry against an old client. The one visible type change is for code that read token.old off registry.routes[...].tokens, which now sees string | undefined.

Measured

On an AdonisJS app with 1142 named routes, .adonisjs/client/registry/index.ts:

	raw	gzip
before	681 kB	40 kB
after	419 kB	24 kB

Verification

• packages/core: 131 tests pass (one added), tsc --noEmit clean, oxlint clean, pnpm build for all packages followed by pnpm typecheck for the whole workspace is clean.
• generate_registry.spec.ts asserts the emitted token JSON contains no "old".
• client.spec.ts adds a case that builds /users/42 with urlFor and issues a request through tuyau.api from a registry whose tokens carry no old. The existing fixtures keep old, so the old shape is still exercised too.