FreeBSD: release tarball and platform docs

The release workflow gains a FreeBSD x86_64 job: packaging/freebsd/package.sh
builds in the same pinned FreeBSD VM and writes a /usr/local-style tar.gz
(app, CLI, desktop entry, MIME type, AppStream metadata, icons, licences).
README and CLAUDE.md list FreeBSD now that its CI job builds PrintCraft and
passes all 688 tests on FreeBSD 14.3.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.github/workflows/release.yml

@@ -201,6 +201,44 @@ jobs:
           path: dist/release/*
           if-no-files-found: error
 
+  freebsd:
+    name: FreeBSD x86_64
+    needs: version
+    # GitHub has no FreeBSD runners: build in a FreeBSD VM (see .github/workflows/freebsd.yml).
+    runs-on: ubuntu-latest
+    environment: release
+    timeout-minutes: 180
+    env:
+      PRINTCRAFT_VERSION: ${{ needs.version.outputs.version }}
+      PRINTCRAFT_BUILD_DATE: ${{ needs.version.outputs.date }}
+      VERSION_OVERRIDE: ${{ inputs.version }}
+    steps:
+      - uses: actions/checkout@v4
+      - name: Build and package in a FreeBSD VM (tar.gz)
+        # vmactions/freebsd-vm v1.5.9, pinned by commit (it runs our build).
+        uses: vmactions/freebsd-vm@c46abacb49f09938ca4e1702d15d836285d694cc
+        with:
+          release: "14.3"
+          usesh: true
+          mem: 12288
+          envs: "PRINTCRAFT_VERSION PRINTCRAFT_BUILD_DATE VERSION_OVERRIDE"
+          prepare: |
+            pkg install -y bash curl git cmake pkgconf llvm19 perl5 \
+              libxkbcommon wayland libX11 libXrandr libXi libXcursor mesa-libs gtk3
+            curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --profile minimal --default-toolchain stable
+          run: |
+            set -e
+            . "$HOME/.cargo/env"
+            git config --global --add safe.directory "$PWD"
+            export LIBCLANG_PATH=/usr/local/llvm19/lib CARGO_BUILD_JOBS=4
+            if [ -n "$VERSION_OVERRIDE" ]; then cargo xtask version set "$PRINTCRAFT_VERSION"; fi
+            packaging/freebsd/package.sh
+      - uses: actions/upload-artifact@v4
+        with:
+          name: release-freebsd-x86_64
+          path: dist/release/*
+          if-no-files-found: error
+
   web:
     name: Web (wasm)
     needs: version
@@ -236,7 +274,7 @@ jobs:
 
   release:
     name: Draft GitHub Release
-    needs: [version, macos, windows, linux, web]
+    needs: [version, macos, windows, linux, freebsd, web]
     runs-on: ubuntu-latest
     environment: release
     permissions: