terms: per-term installer visibility toggles + universal delete (v0.3.4)

- _meta.json: customLabels -> terms.{label,showInInstaller,showInInstallerRp}
- Drop builtin protection; any term kind can be deleted/added/toggled
- New public route /manifest/terms/<pack>/index.json for installer term lists
- Installers fetch terms:list dynamically; skip agreement step if list empty
- Term editor: 2 visibility checkboxes (설치기 / 리소스팩 설치기), multi-select
- Migration from old schema preserves custom labels (default: visible in both)

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/installer-rp/preload.ts

@@ -12,10 +12,14 @@ const api = {
   selectPack: (packKey: string): Promise<void> =>
     ipcRenderer.invoke('rp:packs:select', packKey),
 
-  /** 약관(Markdown) 다운로드. kind: 'resourcepack' | 'installer-rp'. */
+  /** 약관(Markdown) 다운로드. v0.3.4~ : 임의 kind 허용 (사이트에서 설정). */
   getTerm: (kind: string): Promise<{ ok: boolean; content?: string; message?: string }> =>
     ipcRenderer.invoke('rp:terms:get', kind),
 
+  /** rp 인스톨러에 표시할 약관 목록 (사이트의 visibility 토글로 필터링). */
+  getTermsList: (): Promise<{ ok: boolean; terms?: Array<{ kind: string; label: string }>; message?: string }> =>
+    ipcRenderer.invoke('rp:terms:list'),
+
   /** 리소스팩 빌드/설치 시작. 완료 또는 취소될 때까지 resolve 되지 않을 수 있음. */
   startInstall: (): Promise<{ resourcepackPath: string }> =>
     ipcRenderer.invoke('rp:install:start'),