feat: add $state.frozen support (#466)

Author: baseballyama

.changeset/sharp-kangaroos-tease.md

@@ -0,0 +1,5 @@
+---
+"svelte-eslint-parser": patch
+---
+
+feat: add `$state.frozen` support

src/parser/typescript/analyze/index.ts

@@ -318,6 +318,10 @@ function analyzeRuneVariables(
           "<T>(initial: T): T",
           "<T>(): T | undefined",
         ]);
+        appendDeclareNamespaceVirtualScripts(globalName, [
+          "export function frozen<T>(initial: T): Readonly<T>;",
+          "export function frozen<T>(): Readonly<T> | undefined;",
+        ]);
         break;
       }
       case "$derived": {

tests/fixtures/parser/ast/svelte5/docs/runes/01-$state-frozen-input.svelte

@@ -0,0 +1,15 @@
+<script>
+  let numbers = $state.frozen([1, 2, 3]);
+</script>
+
+<button onclick="{() => (numbers = [...numbers, numbers.length + 1])}">
+  push
+</button>
+
+<button onclick="{() => (numbers = numbers.slice(0, -1))}"> pop </button>
+
+<p>
+  {numbers.join(" + ") || 0}
+  =
+  {numbers.reduce((a, b) => a + b, 0)}
+</p>