Make a debug install unmistakable next to the production app, Flutter-style:
- src/debug resource overrides: "Calendula Debug" label and a burnt-orange
launcher-icon background (production stays slate). The .debug applicationId
suffix already lets both install side by side.
- DebugRibbon: a "DEBUG" corner ribbon overlaid in MainActivity, gated on
BuildConfig.DEBUG so release/releaseTest never show it. Enables the
buildConfig feature for the flag.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>