feat(build): cross-platform desktop packaging; bump to 0.1.0

Adds Docker-based packaging for Linux desktop (deb/rpm), Arch
(.pkg.tar.zst via makepkg), and Windows. Windows cross-compiles from
Linux via the official Tauri path — the x86_64-pc-windows-msvc target
driven by cargo-xwin — and produces an NSIS installer (nsis via
tauri.conf.json targets, since the CLI rejects --bundles nsis on a Linux
host). Verified end to end: builds jellytau.exe + jellytau_x64-setup.exe.

Unifies everything on one registry builder image (Dockerfile.builder):
Android SDK/NDK, rpm/file, clang(+clang-cl)/lld/llvm/nsis, cargo-xwin and
the msvc target. Packaging tools sit in a trailing layer so tool changes
rebuild in ~1min instead of ~15. Desktop stages are thin FROM
${BUILDER_IMAGE} layers; Arch uses a separate archlinux image.

CLAUDE.md: CI must install no system toolchains — everything lives in the
image. Bumps version 0.0.18 -> 0.1.0 (Windows support + webview audio +
equalizer).

TRACES: UR-003, UR-005 | DR-004

src-tauri/tauri.conf.json

@@ -1,7 +1,7 @@
 {
   "$schema": "https://schema.tauri.app/config/2",
   "productName": "jellytau",
-  "version": "0.0.18",
+  "version": "0.1.0",
   "identifier": "com.dtourolle.jellytau",
   "build": {
     "beforeDevCommand": "bun run dev",
@@ -23,7 +23,7 @@
   },
   "bundle": {
     "active": true,
-    "targets": ["deb", "rpm"],
+    "targets": ["deb", "rpm", "nsis"],
     "icon": [
       "icons/32x32.png",
       "icons/128x128.png",