feat: add prerequisites, offline prerequisite setup and version tabs

- EXE versions: prerequisite list with the built-in catalog, custom
  installers, download link checks and install file analysis; entries
  are added by the user (no automatic adding), one "추가" dialog with
  기본 목록 / 직접 추가 tabs
- offline prerequisite setup: single exe made from PrerequisiteSetup.exe
  (Windows task dialog, no prerequisites) plus every installer, hash
  checked before, while and after appending; optional WebView2 Runtime
  chosen in the save dialog; replaces an existing file only after the
  user agrees (CLI --replace)
- desktop: progress popup with 생성위치 열기, save dialog fix for
  verbatim paths, EXE 서명 and 설치파일 생성 as version tabs, start
  screen 도구 › 서명하기 placeholder
- CLAUDE.md: results are overwritten only with the user's consent
- test kit and scripts for Windows Sandbox and Hyper-V checks

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/apps/prerequisite-setup/build.rs

@@ -0,0 +1,9 @@
+fn main() {
+    // A clean Windows has no Visual C++ runtime; installing one may be this setup's very job.
+    static_vcruntime::metabuild();
+    // The manifest asks for administrator rights once at start, turns on Common Controls 6 for the
+    // task dialog and per-monitor DPI; the icon is the program's.
+    embed_resource::compile("setup.rc", embed_resource::NONE)
+        .manifest_required()
+        .expect("setup.rc must compile");
+}