Reuse PrioritizedRouteEntry as the Trie entry constraint

`Trie` declared its own `TrieEntry` interface with the same four
fields (`index`, `initialLiteralPrefix`, `literalLength`,
`variableCount`) as `PrioritizedRouteEntry` from *./priority.ts*.  The
duplicate would drift if the priority schema gained a field, since
trie callers and priority helpers are already constrained together.

Drop the local interface and tighten the class generic to
`PrioritizedRouteEntry` so the trie and the ordering helpers share a
single source of truth.

Reported by CodeRabbit in
#758 (2026-05-11).

Assisted-by: Claude Opus 4.7 (1M context)

Author: 2chanhaeng

packages/uri-template/src/router/trie.ts

@@ -1,17 +1,11 @@
 import type { Path } from "../types.ts";
 import Node from "./node.ts";
-
-interface TrieEntry {
-  readonly index: number;
-  readonly initialLiteralPrefix: string;
-  readonly literalLength: number;
-  readonly variableCount: number;
-}
+import type { PrioritizedRouteEntry } from "./priority.ts";
 
 /**
  * Prefix trie for registered route candidates.
  */
-export default class Trie<TEntry extends TrieEntry> {
+export default class Trie<TEntry extends PrioritizedRouteEntry> {
   readonly #root = new Node<TEntry>();
   #dirty = true;