OpenConverter v0.2.1

UI polish

• Sidebar: removed the "Linux audio converter" subtitle. The project is being
  developed for cross-platform support (Linux/macOS/Windows), so this label
  is no longer accurate.
• Sidebar footer: replaced linux/x64 · Node 18.18.2 with
  OpenConverter v<version>. Version is read from app.getVersion() (which
  reads package.json), so it stays accurate regardless of build target.

Verified formats (unchanged from v0.2.0)

• .ncm — 14/14 byte-diff against Python ncmdump
• .qmc0 / .qmc3 / .qmcflac / .qmcogg — round-trip verified
• .kwm — round-trip verified
• .kgm / .kgma / .vpr — round-trip verified
• .mflac / .mflac0 / .mgg / .mgg1 / .bkc* — QMCv2 cipher, requires user-provided ekey from QQ Music client DB (configured in Settings)

Assets

• openconverter_0.2.1_amd64.deb (70 MB)
• openconverter_0.2.1_arm64.deb (65 MB)
• OpenConverter-0.2.1.AppImage (100 MB)
• OpenConverter-0.2.1-arm64.AppImage (100 MB)