The doc-reader bottom-sheet in welcome.dart hits rootBundle
to load assets/docs/<slug>[_de].md. When the asset isn't in
the bundle (e.g. the binary on disk predates the
flutter_markdown_plus migration in 69b54629 or an in-progress
asset reorganisation), the FutureBuilder's error branch dumps
the raw PlatformException text into FaiErrorBox with no
hint at what the operator should do.
Switch the throw to a structured `_DocReaderError` that
carries:
- the slug, locale, and both attempted asset paths
- the underlying error message
- a precomputed `forgejoUrl` pointing at the same doc on
the platform repo's main branch
The error UI gains a TextButton.icon below FaiErrorBox that
opens the Forgejo copy in the OS browser via the existing
SystemActions.openInOs path — operators always have a
working out, even when the local bundle is broken.
The error toString() also surfaces "rebuild Studio" as the
top suggestion, since the most common cause for asset
mismatches is a stale binary running against a newer source
tree.
New regression test (test/load_docs_test.dart) pumps the
exact code path the sheet uses (rootBundle.loadString +
Markdown with FaiTheme.markdownStyle) against all eight asset
paths (architecture/security/audit/flows × en/de). Catches a
future bundle drift before an operator notices.
No behavioural change on the happy path. Both the rendered
markdown widget and the closed-sheet animation are unchanged.
Signed-off-by: flemming-it <stefan.a.flemming@googlemail.com>
