fix: show only line numbers in code snippet chip label

Based on user feedback in Issue #10085, the code reference chip
now displays only line numbers (e.g., "lines 10-25") instead of
file path and line numbers (e.g., "file.ts:10-25") since the code
is always from the current page.

Also adds test coverage for code-snippet module.

packages/types/src/__tests__/code-snippet.test.ts

@@ -0,0 +1,97 @@
+import { describe, it, expect } from "vitest"
+import {
+	CodeSnippet,
+	createCodeSnippetId,
+	formatCodeSnippetLabel,
+	expandCodeSnippet,
+	expandCodeSnippets,
+} from "../code-snippet.js"
+
+describe("code-snippet", () => {
+	describe("createCodeSnippetId", () => {
+		it("should create unique IDs", () => {
+			const id1 = createCodeSnippetId()
+			const id2 = createCodeSnippetId()
+			expect(id1).not.toBe(id2)
+		})
+
+		it("should start with 'snippet-' prefix", () => {
+			const id = createCodeSnippetId()
+			expect(id).toMatch(/^snippet-/)
+		})
+	})
+
+	describe("formatCodeSnippetLabel", () => {
+		it("should format label with only line numbers", () => {
+			const snippet: CodeSnippet = {
+				id: "test-id",
+				filePath: "src/components/Button.tsx",
+				startLine: 10,
+				endLine: 25,
+				content: "const Button = () => {}",
+				timestamp: Date.now(),
+			}
+			expect(formatCodeSnippetLabel(snippet)).toBe("lines 10-25")
+		})
+
+		it("should handle single line snippet", () => {
+			const snippet: CodeSnippet = {
+				id: "test-id",
+				filePath: "index.ts",
+				startLine: 1,
+				endLine: 1,
+				content: "export default {}",
+				timestamp: Date.now(),
+			}
+			expect(formatCodeSnippetLabel(snippet)).toBe("lines 1-1")
+		})
+	})
+
+	describe("expandCodeSnippet", () => {
+		it("should expand snippet to full format with file path", () => {
+			const snippet: CodeSnippet = {
+				id: "test-id",
+				filePath: "src/utils.ts",
+				startLine: 5,
+				endLine: 10,
+				content: "function helper() {\n  return true;\n}",
+				timestamp: Date.now(),
+			}
+			const result = expandCodeSnippet(snippet)
+			expect(result).toContain("src/utils.ts:5-10")
+			expect(result).toContain("```")
+			expect(result).toContain("function helper()")
+		})
+	})
+
+	describe("expandCodeSnippets", () => {
+		it("should expand multiple snippets with spacing", () => {
+			const snippets: CodeSnippet[] = [
+				{
+					id: "test-1",
+					filePath: "file1.ts",
+					startLine: 1,
+					endLine: 5,
+					content: "const a = 1",
+					timestamp: Date.now(),
+				},
+				{
+					id: "test-2",
+					filePath: "file2.ts",
+					startLine: 10,
+					endLine: 15,
+					content: "const b = 2",
+					timestamp: Date.now(),
+				},
+			]
+			const result = expandCodeSnippets(snippets)
+			expect(result).toContain("file1.ts:1-5")
+			expect(result).toContain("file2.ts:10-15")
+			expect(result).toContain("\n\n")
+		})
+
+		it("should return empty string for empty array", () => {
+			expect(expandCodeSnippets([])).toBe("")
+		})
+	})
+})

packages/types/src/code-snippet.ts

@@ -26,11 +26,11 @@ export function createCodeSnippetId(): string {
 }
 
 /**
- * Formats a code snippet for display in a collapsed chip/pill format
+ * Formats a code snippet for display in a collapsed chip/pill format.
+ * Shows only line numbers since the code is always from the current page.
  */
 export function formatCodeSnippetLabel(snippet: CodeSnippet): string {
-	const fileName = snippet.filePath.split("/").pop() || snippet.filePath
-	return `${fileName}:${snippet.startLine}-${snippet.endLine}`
+	return `lines ${snippet.startLine}-${snippet.endLine}`
 }
 
 /**