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

docker-compose.yml

@@ -33,6 +33,58 @@ services:
     ports:
       - "5172:5172"  # In case you want to run dev server
 
+  # Linux desktop packages - deb + rpm + pacman into ./dist
+  desktop-linux-build:
+    build:
+      context: .
+      dockerfile: Dockerfile
+      target: desktop-linux-build
+      args:
+        # Defaults to the registry builder (Dockerfile's ARG). Point at a locally
+        # built builder with: BUILDER_IMAGE=jellytau-builder:latest docker compose ...
+        BUILDER_IMAGE: ${BUILDER_IMAGE:-gitea.tourolle.paris/dtourolle/jellytau-builder:latest}
+    container_name: jellytau-desktop-linux-build
+    volumes:
+      - .:/app
+      - cargo-cache:/root/.cargo
+      - bun-cache:/root/.bun
+    environment:
+      - RUST_BACKTRACE=1
+      - OUTPUT_DIR=/app/dist
+    command: bash -c "OUTPUT_DIR=/app/dist scripts/build-desktop-linux.sh"
+
+  # Arch Linux package (.pkg.tar.zst via makepkg) into ./dist
+  arch-build:
+    build:
+      context: .
+      dockerfile: Dockerfile.arch
+    container_name: jellytau-arch-build
+    volumes:
+      - ./dist:/out
+    environment:
+      - RUST_BACKTRACE=1
+      - OUTPUT_DIR=/out
+
+  # Windows cross-compile (MSVC via cargo-xwin). Emits NSIS installer + .exe to
+  # ./dist. Override WIN_BUNDLES=none for exe-only.
+  windows-cross:
+    build:
+      context: .
+      dockerfile: Dockerfile
+      target: windows-cross
+      args:
+        BUILDER_IMAGE: ${BUILDER_IMAGE:-gitea.tourolle.paris/dtourolle/jellytau-builder:latest}
+    container_name: jellytau-windows-cross
+    volumes:
+      - .:/app
+      - cargo-cache:/root/.cargo
+      - bun-cache:/root/.bun
+    environment:
+      - RUST_BACKTRACE=1
+      - OUTPUT_DIR=/app/dist
+      - WIN_BUNDLES=${WIN_BUNDLES:-nsis}
+    command: bash -c "OUTPUT_DIR=/app/dist WIN_BUNDLES=${WIN_BUNDLES:-nsis} scripts/build-windows-cross.sh"
+
   # Development container - for interactive development
   dev:
     build: