Add routines module and full goal management

Routines: workout, meditation and must-do routines with timed, rep and
tick steps, sets and rest. A library screen, a builder with templates
and drag-to-reorder steps, and a full-screen player that auto-advances
timed phases, counts backgrounding and logs broken chains as partial.

Goals: a goal editor (deadline, colour, category, default class, archive),
routines linked to goals, and a goal field on tasks and routines. Tasks
added from inside a goal are now actually attached to it via parentId.

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

frontend/lib/Grounded/utils/Thresholds.dart

@@ -36,4 +36,12 @@ class Thresholds {
 
   /// Minutes a push can go unacknowledged before SMS fallback fires.
   static const int smsFallbackMinutes = 20;
+
+  /// Routine runner: the last seconds of a timed phase tick with a haptic, so
+  /// the change of phase never arrives unannounced.
+  static const int routineCountdownSeconds = 3;
+
+  /// A routine stopped before this fraction of its steps is logged as broken
+  /// rather than partial.
+  static const double routinePartialFloor = 0.5;
 }