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/utils/Validators.dart

@@ -0,0 +1,80 @@
+import 'Thresholds.dart';
+
+/// Field-level validation. Returns null when valid, so it drops straight into
+/// a TextFormField validator.
+class Validators {
+  static String? required(String? value, String field) {
+    if (value == null || value.trim().isEmpty) {
+      return "$field is required.";
+    }
+    return null;
+  }
+
+  static String? title(String? value) {
+    final String? empty = required(value, "Title");
+    if (empty != null) {
+      return empty;
+    }
+    if (value!.trim().length < 3) {
+      return "Give it a name you will recognise later.";
+    }
+    return null;
+  }
+
+  /// The excuse gate. Free text only, minimum length, no template buttons —
+  /// the friction is the point.
+  static String? excuse(String? value) {
+    if (value == null || value.trim().isEmpty) {
+      return "An excuse is required to defer.";
+    }
+    if (value.trim().length < Thresholds.minExcuseLength) {
+      return "Write at least ${Thresholds.minExcuseLength} characters.";
+    }
+    return null;
+  }
+
+  static String? estimateMinutes(String? value) {
+    final String? empty = required(value, "Estimate");
+    if (empty != null) {
+      return empty;
+    }
+    final int? minutes = int.tryParse(value!.trim());
+    if (minutes == null || minutes <= 0) {
+      return "Enter the minutes you think it will take.";
+    }
+    if (minutes > 720) {
+      return "Nothing on a daily plan takes more than 12 hours. Split it.";
+    }
+    return null;
+  }
+
+  /// A window, not a date. The end must actually close after the start.
+  static String? window(DateTime? start, DateTime? end) {
+    if (start == null || end == null) {
+      return "Set a due window, not just a day.";
+    }
+    if (!end.isAfter(start)) {
+      return "The window has to close after it opens.";
+    }
+    return null;
+  }
+
+  static String? username(String? value) {
+    final String? empty = required(value, "Username");
+    if (empty != null) {
+      return empty;
+    }
+    return null;
+  }
+
+  static String? password(String? value) {
+    final String? empty = required(value, "Password");
+    if (empty != null) {
+      return empty;
+    }
+    if (value!.length < 8) {
+      return "Passwords are at least 8 characters.";
+    }
+    return null;
+  }
+}