Initial commit: Grounded Flutter frontend

A to-do app that doesn't believe you — an enforcement layer rather than a
neutral ledger.

Architecture ported from Autoreceptives/Frontend/Receptive: stacked MVVM with
the mandatory 4-file screen pattern, one ParentViewModel owning the loading /
network / error overlays and the handleError decision tree, one AppDataManager
gateway, dio comms carrying the three identity headers, secure storage with
random-suffixed keys, and a single-chokepoint Navigator. Package root and Dart
package name are both Grounded; org is nya.

The enforcement engine, one unit per formula in utils/:

- DebtEngine      w(class) x severity(d) x decay(t), sublinear severity so old
                  misses cannot swamp the score; abandonment 2x with 30-day
                  decay immunity; late complete retains 30%
- StandingEngine  Good -> Warned -> Grounded -> Lockdown, derived not set;
                  Grounded replaces home with the overdue queue
- CapacityEngine  blocks over-scheduling against p50 of historically completed
                  minutes, with a learned per-category estimation multiplier
- IntegrityEngine session integrity, weekly volume, plyometric contact ceiling
                  and enforced recovery gaps
- ExcuseAnalyser  on-device excuse clustering plus the confrontation copy
- GuardrailEngine distress detection and rationed amnesty
- ToneEngine      all enforcement copy, so the tone cap lives in one place

CommitmentEvent is append-only and is the source of truth rather than the
status field, which is what makes honest history and excuse analysis possible.

Goals contain commitments via parentId, and a task can be run from a
full-screen runner that derives elapsed time from wall-clock so screen-off
cannot lose time. Backgrounding pauses the clock and is counted. The runner is
mirrored into an ongoing notification, with alarm-class full-screen intents
reserved for non-negotiables.

Design language, fonts, icon and native splash are in place; Mason bricks are
retargeted to this project and verified end-to-end.

flutter analyze lib/ reports no errors.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Mfu2gQLSFN21YRBcU2NrTt

frontend/lib/Grounded/about/external/data/Habit.dart

@@ -0,0 +1,73 @@
+/// Frequency-based rather than instance-based: a single miss costs nothing,
+/// falling below the target in the rolling window is what accrues debt.
+class Habit {
+  String? id;
+
+  String title;
+
+  String category;
+
+  /// Target completions per rolling window, e.g. 5.
+  int targetPerWindow;
+
+  /// Rolling window length in days, e.g. 7.
+  int windowDays;
+
+  /// Completions inside the current window.
+  int completionsInWindow;
+
+  /// Marked keystone once the data says its completion predicts day quality —
+  /// the app works this out after ~60 days rather than taking your word.
+  bool keystone;
+
+  /// 0..1 correlation with overall day quality; -1 until there is enough data.
+  double predictiveStrength;
+
+  Habit({
+    this.id,
+    this.title = "",
+    this.category = "",
+    this.targetPerWindow = 0,
+    this.windowDays = 7,
+    this.completionsInWindow = 0,
+    this.keystone = false,
+    this.predictiveStrength = -1,
+  });
+
+  factory Habit.fromJson(Map<String, dynamic> json) {
+    return Habit(
+      id: json['id'],
+      title: json['title'] ?? "",
+      category: json['category'] ?? "",
+      targetPerWindow: json['targetPerWindow'] ?? 0,
+      windowDays: json['windowDays'] ?? 7,
+      completionsInWindow: json['completionsInWindow'] ?? 0,
+      keystone: json['keystone'] ?? false,
+      predictiveStrength: (json['predictiveStrength'] ?? -1).toDouble(),
+    );
+  }
+
+  Map<String, dynamic> toJson() {
+    final Map<String, dynamic> data = <String, dynamic>{};
+    data['id'] = id;
+    data['title'] = title;
+    data['category'] = category;
+    data['targetPerWindow'] = targetPerWindow;
+    data['windowDays'] = windowDays;
+    data['completionsInWindow'] = completionsInWindow;
+    data['keystone'] = keystone;
+    data['predictiveStrength'] = predictiveStrength;
+    return data;
+  }
+
+  /// Behind target for the window — the only condition under which a habit
+  /// accrues debt.
+  bool get behindTarget {
+    return completionsInWindow < targetPerWindow;
+  }
+
+  int get shortfall {
+    final int gap = targetPerWindow - completionsInWindow;
+    return gap > 0 ? gap : 0;
+  }
+}