Preview/PR builds don't have access to GitHub Secrets, so the OAuth
client IDs are empty. Previously this caused a runtime crash from
keys.dart throwing on empty values. Now we detect missing secrets
and force simulate mode, which already fully supports fake auth
and uploads.
Also fixes a latent bug where forceLogin() would crash with
LateInitializationError in simulate mode since _helper is never
initialized when OAuth setup is skipped.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Create UserAgentClient (http.BaseClient wrapper) that injects a
User-Agent header into every request, reading app name and version
from VersionService and contact/homepage from dev_config.dart.
Format follows OSM tile usage policy:
DeFlock/<version> (+https://deflock.org; contact: admin@stopflock.com)
Replaces 4 inconsistent hardcoded UA strings and adds UA to the 9
call sites that previously sent none.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Fixes avoid_print lint warnings by using debugPrint which respects
release mode and avoids console overflow on mobile platforms.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
