Pause polling and show a banner when the backend is unreachable

Adds a centralized BackendReachability singleton fed by a Dio
interceptor (connection-level failures only) and connectivity_plus.
PolledValue subscribes to it and pauses on offline / reloads
immediately on reconnect, replacing the previous per-card error
cascade. MainShell renders a global OfflineBanner with Retry and
Settings actions; cards downgrade error→stale when offline so the
banner is the only red element.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
This commit is contained in:
rzuasti
2026-05-31 18:21:55 -04:00
co-authored by Claude Sonnet 4.6
parent 8be65f3ffa
commit b5da90be59
15 changed files with 388 additions and 47 deletions
@@ -3,6 +3,7 @@
#
list(APPEND FLUTTER_PLUGIN_LIST
connectivity_plus
encrypter
url_launcher_windows
)