Flatpak: fonts a font manager activates into ~/.fonts are visible

Flatpak opens only /usr/share/fonts and ~/.local/share/fonts to a sandbox, so the
fonts a font manager such as FontBase activates into ~/.fonts were missing from the
font list while native apps showed them. Granted read-only: VectorCraft only reads
fonts.

Verified on the 0.11.0 release bundle by applying the same grant as a user override
(`flatpak override --user --filesystem=~/.fonts:ro`): in a fresh sandbox the FontBase
families went from none to all 167, `fc-match` resolved a family that had been missing
from the app, and the font then appeared in the font list.

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

packaging/linux/flatpak/ai.storyteller.vectorcraft.bundle.yml

@@ -28,9 +28,13 @@ finish-args:
   # portal, so broad filesystem access isn't needed. Pictures is granted for opening files by
   # path from the command line.
   - --filesystem=xdg-pictures
+  # Font managers (FontBase and others) activate fonts into ~/.fonts, which Flatpak does not open
+  # to a sandbox: it exposes /usr/share/fonts and ~/.local/share/fonts, and nothing else. Without
+  # this the font list holds none of the activated families, while native apps see them.
+  - --filesystem=~/.fonts:ro
   # Deliberately not granted: network (the optional --control server listens on 127.0.0.1 in
   # the sandbox; `flatpak override --user --share=network ai.storyteller.vectorcraft` exposes it
-  # to host agents) and home/host filesystem access.
+  # to host agents) and home/host filesystem access beyond the read-only folders above.
 modules:
   - name: vectorcraft
     buildsystem: simple

packaging/linux/flatpak/ai.storyteller.vectorcraft.yml

@@ -26,6 +26,7 @@ finish-args:
   # portal, so broad filesystem access isn't needed. Pictures is granted for opening files by
   # path from the command line.
   - --filesystem=xdg-pictures
+  - --filesystem=~/.fonts:ro
 build-options:
   append-path: /usr/lib/sdk/rust-stable/bin
 modules: