fix(svelte,vue): a component's instance script declarations are its own (#2227)

isVisibleAcrossFiles rejects a declaration in a .svelte instance <script> or a
Vue <script setup> from another file; a Svelte <script module>, a plain Vue
<script>, and a type a <script setup> exports stay reachable.

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

__tests__/sfc-private-declarations.test.ts

@@ -0,0 +1,94 @@
+/**
+ * What a Svelte component's instance `<script>` or a Vue SFC's `<script setup>`
+ * declares is the component's own — no other file reaches it by name. Only a
+ * Svelte `<script module>`, a Vue `<script>` that is not `setup`, or a type a
+ * `<script setup>` exports can be imported. shadcn-svelte's `<Item.Root>` (a
+ * namespace import) went to a `type Item` one example component declares,
+ * and halo's `isActive` from `@/tiptap/core` to a tab's local `computed`.
+ */
+import { describe, it, expect, afterAll, beforeAll } from 'vitest';
+import * as fs from 'fs';
+import * as os from 'os';
+import * as path from 'path';
+import { CodeGraph } from '../src';
+
+let root = '';
+let cg: CodeGraph;
+
+beforeAll(async () => {
+  root = fs.mkdtempSync(path.join(os.tmpdir(), 'cg-sfc-private-'));
+  const files: Record<string, string> = {
+    'package.json': JSON.stringify({ name: 'docs', private: true }),
+    'src/lib/examples/attachment-group.svelte': `<script lang="ts">
+	type Item = {
+		name: string;
+	};
+	const items: Item[] = [];
+</script>
+
+<div>{items.length}</div>
+`,
+    'src/lib/examples/item-demo.svelte': `<script lang="ts">
+	import * as Item from "$lib/ui/item/index.js";
+	let label: Item = null;
+</script>
+
+<Item.Root>{label}</Item.Root>
+`,
+    'src/components/TabItem.vue': `<script lang="ts" setup>
+import { computed } from "vue";
+const isActive = computed(() => true);
+</script>
+
+<template><div v-if="isActive" /></template>
+`,
+    'src/extensions/code-block.ts': `import { isActive } from "@/tiptap/core";
+
+export function active(state: unknown) {
+  return isActive(state);
+}
+`,
+    'src/components/CrudTable.vue': `<script setup lang="ts">
+export interface TableConfig {
+  hideColumns: boolean;
+}
+defineProps<{ config: TableConfig }>();
+</script>
+
+<template><table /></template>
+`,
+    'src/pages/GroupDataPage.vue': `<script setup lang="ts">
+import type { TableConfig } from "~/components/CrudTable.vue";
+const config: TableConfig = { hideColumns: false };
+</script>
+
+<template><div>{{ config }}</div></template>
+`,
+  };
+  for (const [rel, content] of Object.entries(files)) {
+    fs.mkdirSync(path.dirname(path.join(root, rel)), { recursive: true });
+    fs.writeFileSync(path.join(root, rel), content);
+  }
+  cg = await CodeGraph.init(root, { index: true });
+});
+
+afterAll(() => {
+  cg?.close();
+  if (root) fs.rmSync(root, { recursive: true, force: true });
+});
+
+const targetsFrom = (file: string) => {
+  const ids = cg.getNodesInFile(file).map((n) => n.id);
+  return cg.getOutgoingEdgesFrom(ids).filter((e) => e.kind !== 'contains').map((e) => cg.getNode(e.target)!).map((t) => `${t.filePath}:${t.name}`);
+};
+
+describe('single-file component declarations', () => {
+  it('are private to the component', () => {
+    expect(targetsFrom('src/lib/examples/item-demo.svelte')).not.toContain('src/lib/examples/attachment-group.svelte:Item');
+    expect(targetsFrom('src/extensions/code-block.ts')).not.toContain('src/components/TabItem.vue:isActive');
+  });
+
+  it('except a type a Vue <script setup> exports', () => {
+    expect(targetsFrom('src/pages/GroupDataPage.vue')).toContain('src/components/CrudTable.vue:TableConfig');
+  });
+});