feat(linux): native build path + Linux-specific launcher optimizations

- X-Plane auto-detection now finds Steam (native + Flatpak), /opt and
  external-drive SteamLibrary installs, not just ~/ and macOS/Windows paths.
- Close-to-background minimizes on Linux instead of hiding to tray, so the app
  is never stranded on desktops without a tray (e.g. vanilla GNOME).
- Disable WebKitGTK's DMABUF renderer on Linux to avoid black/blank windows on
  some GPU/driver combos (overridable via the env var).
- Launcher font stack gains Linux UI/mono fallbacks (Cantarell/Ubuntu/Noto).
- scripts/build.sh: Docker-free Linux AppImage build — repack the cockpit into
  the prebuilt bundle for web-only changes; recompile natively for code changes.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

scripts/build.sh

@@ -0,0 +1,94 @@
+#!/usr/bin/env bash
+# Build the Linux artifacts (AppImage + .deb) WITHOUT Docker and WITHOUT
+# recompiling the Rust launcher.
+#
+# WHY: this app's launcher (Tauri/Rust) barely ever changes — what changes is the
+# cockpit itself (web/ JSX), which ships as a *resource* the Bun sidecar serves at
+# runtime. So a release is really just: rebuild the web cockpit, drop it into the
+# already-compiled bundle, and repack. That's seconds, not a Docker cross-build.
+#
+# It reuses three things produced by a prior full `tauri build`:
+#   * the compiled launcher + GTK/WebKit libs in the AppDir
+#   * the cached linuxdeploy appimage packer (~/.cache/tauri/...)
+#   * the seed .deb (for its control metadata + file tree)
+# and refreshes the cockpit (usr/lib/X-Plane Cockpit/web) + Lua plugins in both.
+#
+# Seed once (native, no Docker) if the AppDir is missing:
+#   scripts/prep-desktop.sh
+#   npx --prefix desktop tauri build --target x86_64-unknown-linux-gnu --bundles appimage,deb
+# Thereafter just run this script for every web-only change.
+#
+# CAVEAT: the launcher binary is reused as-is, so the *version it reports itself*
+# (used by the auto-updater) is whatever it was last compiled with — not
+# necessarily $VERSION. The cockpit features are unaffected (they come from the
+# refreshed web resources). If you bump the version AND rely on the updater,
+# recompile the launcher once with the tauri build line above.
+set -euo pipefail
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"; cd "$ROOT"
+die(){ echo "!! $*" >&2; exit 1; }
+
+TARGET=x86_64-unknown-linux-gnu
+BUNDLE="$ROOT/target-linux/$TARGET/release/bundle"
+APPDIR="$BUNDLE/appimage/X-Plane Cockpit.AppDir"
+RESDIR="$APPDIR/usr/lib/X-Plane Cockpit"
+PLUGIN="$HOME/.cache/tauri/linuxdeploy-plugin-appimage.AppImage"
+SIDECAR="$ROOT/desktop/src-tauri/binaries/xpbridge-$TARGET"
+PKGNAME="X-Plane Cockpit"
+VERSION="$(node -p "require('$ROOT/desktop/src-tauri/tauri.conf.json').version")"
+
+echo "==> X-Plane Cockpit Linux repack — v$VERSION (no Docker, no Rust recompile)"
+
+# ---- preflight -----------------------------------------------------------
+[[ -d "$APPDIR" ]]  || die "no prebuilt AppDir: $APPDIR — seed one full tauri build first (see header)"
+[[ -x "$PLUGIN" ]]  || die "missing appimage packer: $PLUGIN — run one tauri appimage build to fetch it"
+[[ -f "$SIDECAR" ]] || die "missing sidecar: $SIDECAR — run scripts/prep-desktop.sh"
+command -v ar  >/dev/null || die "'ar' (binutils) required to assemble the .deb"
+command -v tar >/dev/null || die "'tar' required"
+
+SIGN=0
+[[ -f desktop/.tauri-signing.key && -f desktop/.tauri-signing.pw ]] && SIGN=1
+sign(){ # $1 = artifact; writes <artifact>.sig next to it
+  if [[ $SIGN == 1 ]]; then
+    TAURI_SIGNING_PRIVATE_KEY="$(cat desktop/.tauri-signing.key)" \
+    TAURI_SIGNING_PRIVATE_KEY_PASSWORD="$(cat desktop/.tauri-signing.pw)" \
+      npx --prefix desktop tauri signer sign "$1" >/dev/null
+    echo "   signed: $(basename "$1").sig"
+  else
+    rm -f "$1.sig"
+  fi
+}
+
+# ---- 1. build the web cockpit, refresh repo resources --------------------
+echo "==> building web cockpit (vite)"
+( cd web && npm run build >/dev/null )
+echo "==> refreshing desktop/src-tauri/resources"
+rm -rf "desktop/src-tauri/resources/web";     mkdir -p "desktop/src-tauri/resources/web"
+cp -R web/dist/. "desktop/src-tauri/resources/web/"
+rm -rf "desktop/src-tauri/resources/plugins"; mkdir -p "desktop/src-tauri/resources/plugins"
+cp plugins/*.lua "desktop/src-tauri/resources/plugins/"
+
+# ---- 2. refresh the cockpit inside the prebuilt AppDir -------------------
+echo "==> updating bundled cockpit inside AppDir"
+rm -rf "$RESDIR/web";     mkdir -p "$RESDIR/web";     cp -R web/dist/. "$RESDIR/web/"
+rm -rf "$RESDIR/plugins"; mkdir -p "$RESDIR/plugins"; cp plugins/*.lua "$RESDIR/plugins/"
+# the AppDir's sidecar copy may be a patchelf-corrupted one — restore the pristine
+cp -f "$SIDECAR" "$APPDIR/usr/bin/xpbridge"; chmod +x "$APPDIR/usr/bin/xpbridge"
+
+# ---- 3. pack the AppImage (cached linuxdeploy plugin, no patchelf) -------
+OUTIMG="$BUNDLE/appimage/${PKGNAME}_${VERSION}_amd64.AppImage"
+echo "==> packing AppImage -> $(basename "$OUTIMG")"
+rm -f "$OUTIMG"
+APPIMAGE_EXTRACT_AND_RUN=1 NO_STRIP=1 ARCH=x86_64 LDAI_OUTPUT="$OUTIMG" \
+  "$PLUGIN" --appdir "$APPDIR" >/dev/null
+[[ -f "$OUTIMG" ]] || die "AppImage packing produced nothing"
+chmod +x "$OUTIMG"
+sign "$OUTIMG"
+echo "   AppImage: $(du -h "$OUTIMG" | cut -f1)"
+
+# The .deb is intentionally NOT built: the AppImage is the single self-contained,
+# self-updating artifact (the Tauri Linux updater swaps the AppImage in place; it
+# never uses a .deb). If you ever want a .deb too, run a full native tauri build
+# with --bundles appimage,deb.
+
+echo "==> done. artifact:"
+ls -1 "$OUTIMG"