feat(packaging): portable mode and AppImage desktop integration (M8)

.github/workflows/packaging-lint.yml

@@ -22,6 +22,27 @@ jobs:
     # Intentionally tracked at @main (not SHA-pinned) so org-wide CI improvements, security fixes, and build optimizations propagate without PR churn across all craftapp repos.
     uses: storytold/craft-common-actions/.github/workflows/packaging-lint.yml@main
 
+  # Store readiness (ADR 0094): the metadata Flathub, AppStream consumers and winget/MSIX read.
+  # Checks only; nothing is submitted (submissions are the team's job, docs/release.md).
+  store-readiness:
+    timeout-minutes: 10
+    name: Store readiness (Flatpak, AppStream, winget/MSIX)
+    runs-on: ubuntu-24.04
+    steps:
+      - name: Harden runner
+        uses: step-security/harden-runner@1d88384fd173af6ecb012dfd0264a306b711241a # v2.22.4
+        with:
+          egress-policy: audit
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          persist-credentials: false
+      - name: Install the validators
+        run: |
+          sudo apt-get update -qq
+          sudo apt-get install -y --no-install-recommends appstream desktop-file-utils python3-yaml
+      - name: Check store metadata
+        run: packaging/check-store-readiness.sh
+
   windows-install-policy:
     timeout-minutes: 15
     name: Windows installation policy (no app build)

ATTRIBUTION.md

@@ -87,6 +87,7 @@ OR Apache-2.0) is noted in the table.
 | Hairlines: coverage falling off with the distance from the pixel centre to the line | `crates/render/src/hairline.rs`, `crates/gpu/src/fine.wgsl` | S. Gupta and R. F. Sproull, *Filtering Edges for Gray-Scale Displays* (SIGGRAPH 1981): anti-aliased lines by distance; standard | Public method; a one-pixel tent filter of the distance (ADR 0048). |
 | Plural categories for whole numbers (zero, one, two, few, many, other) | `src/i18n/plural.rs` | Unicode CLDR, *Language Plural Rules* (`common/supplemental/plurals.xml`), <https://cldr.unicode.org>, Unicode License v3 (Unicode-3.0) | The integer rules rewritten as Rust `match`es from the published rules; no CLDR data file is bundled. |
 | Stage elements as a multi-select list box; menu bar keyboard model (Alt/F10, arrows, access keys) | `src/stage_a11y.rs`, `src/menus.rs` | W3C *WAI-ARIA Authoring Practices Guide*, Listbox and Menubar patterns, <https://www.w3.org/WAI/ARIA/apg/> (W3C Software and Document License) | Keyboard behaviour learned from the published patterns; no code or text copied. |
+| Desktop integration of an AppImage: desktop entry `Exec` quoting and string escapes, MIME packages, hicolor icons, the user's data folder | `crates/engine/src/cmds_desktop.rs`, `src/platform.rs` | freedesktop.org *Desktop Entry Specification* 1.5, *Shared MIME-info Database*, *Icon Theme Specification*, *XDG Base Directory Specification*, <https://specifications.freedesktop.org/>; AppImage documentation on `$APPIMAGE` (public docs) | Written from the specifications (ADR 0094); no code copied. |
 | Reading the desktop's contrast setting | `src/platform.rs` | *XDG Desktop Portal*, Settings interface, `org.freedesktop.appearance` `contrast` key, <https://flatpak.github.io/xdg-desktop-portal/> (LGPL documentation, read only; nothing bundled or linked) | One value read through the `gdbus` tool. |
 | Interface catalog format (TSV keyed by English, `@plural`/`@id` rows, fallback order) | `src/i18n/catalog.rs`, `build.rs` | storytold/craft-i18n `docs/catalog-format.md` and `docs/integration.md` (MIT OR Apache-2.0, same project family) | Our own parser written from those documents; the craft-libs `craft-i18n` crate is not used (ADR 0040). |
 | Adaptive Bézier flattening (Wang's formula) | `crates/geom/src/path.rs` | G.-J. Wang (1984); public mathematical result | |

CHANGELOG.md

@@ -2,6 +2,23 @@
 
 ## Unreleased
 
+* **Portable copies and AppImage desktop integration** (ADR 0094, M8).
+  * **The Windows zip and the Linux tar.gz are portable**: preferences, autosaved work, logs,
+    plug-ins, templates, brushes, filter presets, workspaces and recent files stay in a `data`
+    folder beside AniCraft. A file named `anicraft-portable` next to the program (or next to
+    `AniCraft.app` or an `.AppImage`) is what makes a copy portable; delete it to use your user
+    folder. A portable folder that can't be written falls back to your user folder and says so.
+  * **Preferences › About** shows the version, whether this copy is installed or portable, and
+    every folder AniCraft keeps things in, each with an Open button.
+  * **AppImage: Add to Menu.** The first start from an AppImage offers once, in a card that
+    nothing waits on, to add AniCraft to your applications menu and open `.anicraft`, `.fla` and
+    `.xfl` files with it. Only `~/.local/share` changes; Preferences › About removes it again,
+    and the entry follows the AppImage when you move or update it. Headless:
+    `desktop.integrate`, `desktop.remove`, `desktop.status`.
+  * **Store readiness:** a Packaging lint job validates the Flatpak manifests, the AppStream
+    metainfo (`appstreamcli validate`), the desktop entry and any winget or MSIX manifests.
+    Nothing is submitted.
+
 * **Brushes and erasing, second slice: tilt, textured brushes, erasing inside symbols, profiles
   in the merge** (ADR 0093, M7).
   * **Pen tilt** shapes the Brush: it turns the tip with the way the pen leans and paints up