Rebuild Home around a forest header with streak, score and water

Home now opens on a deep green header: greeting, a Today / Weekly toggle,
a seven-day streak with a leaf on every kept day, minutes held with a +
ring, plan thumbnails, the report-card letter as the score, and one bar per
commitment class (weekly view swaps in per-day bars and class rates). The
+ opens an "Add to today" sheet over the blurred day. A water tracker sits
below the header, kept on the device. The nav marks the selected tab as a
filled block and drops the side action button.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KhQh614DMeYoQEH9SoMRUw

frontend/lib/Grounded/memory/ConnectInternalMemory.dart

@@ -60,6 +60,11 @@ abstract class ConnectInternalMemory {
 
   Future setAmnestySpent(int spent);
 
+  /// Water drunk today in ml; a new day reads as 0.
+  Future<int> getWaterToday();
+
+  Future setWaterToday(int ml);
+
   /// The quick to-do list on Home.
   Future<List<TodoItem>> getTodos();