Linux app id: ai.storyteller.solidcraft, with an end-of-life rebase from the old id (#619)

The Flatpak app id, desktop/metainfo/MIME file names, icon name and the window's Wayland app_id / X11 class are now ai.storyteller.solidcraft, the id the ArtCraft launcher expects.

Existing Flatpak installs move over: the Pages repo marks app/ai.storyteller.solvecraft end-of-life with a rebase to the new id, so flatpak update offers the switch and Flatpak carries ~/.var/app along. A new install next to the old one copies settings and autosaves on first launch through a read-only grant on the old data folder. The metainfo declares <replaces>/<provides>, the desktop entry X-Flatpak-RenamedFrom, and AppImages drop the menu entry an older AppImage installed. deb/rpm upgrades remove the old-named files.

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

.github/release-notes.md

@@ -73,10 +73,13 @@ installing SolidCraft; keep both remotes in the same user installation:
 ```sh
 flatpak remote-add --user --if-not-exists flathub https://dl.flathub.org/repo/flathub.flatpakrepo
 flatpak remote-add --user --if-not-exists solidcraft https://bherbruck.github.io/solidcraft/flatpak/solidcraft.flatpakrepo
-flatpak install --user solidcraft ai.storyteller.solvecraft
-flatpak run ai.storyteller.solvecraft
+flatpak install --user solidcraft ai.storyteller.solidcraft
+flatpak run ai.storyteller.solidcraft
 ```
 
+Flatpak installs from 0.7 or earlier use the old ID `ai.storyteller.solvecraft`: `flatpak update --user`
+offers to replace it with `ai.storyteller.solidcraft`, and settings move along.
+
 Single-file `.flatpak` bundles include the runtime repository address; missing runtimes
 still need an internet connection. [Linux installation details](https://bherbruck.github.io/solidcraft/guide/getting-started.html#linux-flatpak).