feat(export): extras 오버라이드 지원(robots/manifest) TDD 및 구현

lib/exporter/extras.ts

@@ -1,13 +1,25 @@
 import type { Page } from '@/lib/schema/page'
 
+type ExtrasOverrides = {
+  robotsText?: string
+  manifest?: Partial<{
+    name: string
+    short_name: string
+    start_url: string
+    display: string
+    theme_color: string
+  }>
+}
+
 // Sheets 템플릿 등 ZIP 루트/서브 경로에 포함할 추가 파일(extras)을 구성한다.
 // - actionUrl이 비어있을 때만 Google Apps Script 템플릿을 포함한다.
-export function buildExtrasForPage(page: Page): Record<string, Uint8Array> {
+export function buildExtrasForPage(page: Page, overrides?: ExtrasOverrides): Record<string, Uint8Array> {
   const extras: Record<string, Uint8Array> = {}
   const te = new TextEncoder()
 
   // Always provide a baseline robots.txt
-  const robots = `User-agent: *\nDisallow:`
+  const robotsDefault = `User-agent: *\nDisallow:`
+  const robots = overrides?.robotsText ?? robotsDefault
   extras['robots.txt'] = te.encode(robots)
 
   // Provide a minimal site.webmanifest derived from Page
@@ -20,6 +32,13 @@ export function buildExtrasForPage(page: Page): Record<string, Uint8Array> {
       start_url: '/',
       display: 'standalone',
       theme_color: page.theme?.primaryColor ?? '#000000',
+      ...((overrides?.manifest as object) || {}),
+    } as {
+      name: string
+      short_name: string
+      start_url: string
+      display: string
+      theme_color: string
     }
     extras['site.webmanifest'] = te.encode(JSON.stringify(manifest))
   } catch {}