chore(release): prepare for v3.6.1 release

- Bump version to 3.6.1 across all config files
  - package.json, Cargo.toml, tauri.conf.json
  - README.md and README_ZH.md version badges
  - Auto-updated Cargo.lock
- Add release notes documentation
  - docs/release-note-v3.6.0-en.md (archive)
  - docs/release-note-v3.6.1-zh.md (cumulative format)
  - docs/release-note-v3.6.1-en.md (cumulative format)
- Enlarge PackyCode sponsor logo by 50% (100px → 150px)
- Update roadmap checklist (homebrew support marked as done)

src-tauri/Cargo.lock

@@ -563,7 +563,7 @@ dependencies = [
 
 [[package]]
 name = "cc-switch"
-version = "3.6.0"
+version = "3.6.1"
 dependencies = [
  "chrono",
  "dirs 5.0.1",