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/about/external/data/RoutineStep.dart

@@ -0,0 +1,75 @@
+import '../../internal/application/StepMode.dart';
+
+class RoutineStep {
+  String? id;
+
+  String title;
+
+  int order;
+
+  StepMode mode;
+
+  /// Work seconds per set for timed steps; the estimate per set otherwise.
+  int timerSeconds;
+
+  int sets;
+
+  /// Target per set for rep steps; 0 otherwise.
+  int reps;
+
+  /// Rest between sets, and after the last set before the next step.
+  int restSeconds;
+
+  /// One line shown under the clock — a form cue, a breathing pattern.
+  String cue;
+
+  bool completed;
+
+  RoutineStep({
+    this.id,
+    this.title = "",
+    this.order = 0,
+    this.mode = StepMode.Timed,
+    this.timerSeconds = 0,
+    this.sets = 1,
+    this.reps = 0,
+    this.restSeconds = 0,
+    this.cue = "",
+    this.completed = false,
+  });
+
+  factory RoutineStep.fromJson(Map<String, dynamic> json) {
+    return RoutineStep(
+      id: json['id'],
+      title: json['title'] ?? "",
+      order: json['order'] ?? 0,
+      mode: getStepMode(json['mode']),
+      timerSeconds: json['timerSeconds'] ?? 0,
+      sets: json['sets'] ?? 1,
+      reps: json['reps'] ?? 0,
+      restSeconds: json['restSeconds'] ?? 0,
+      cue: json['cue'] ?? "",
+      completed: json['completed'] ?? false,
+    );
+  }
+
+  Map<String, dynamic> toJson() {
+    final Map<String, dynamic> data = <String, dynamic>{};
+    data['id'] = id;
+    data['title'] = title;
+    data['order'] = order;
+    data['mode'] = mode.name;
+    data['timerSeconds'] = timerSeconds;
+    data['sets'] = sets;
+    data['reps'] = reps;
+    data['restSeconds'] = restSeconds;
+    data['cue'] = cue;
+    data['completed'] = completed;
+    return data;
+  }
+
+  int get plannedSeconds {
+    final int safeSets = sets < 1 ? 1 : sets;
+    return timerSeconds * safeSets + restSeconds * safeSets;
+  }
+}