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/see/commitment/NewCommitment.dart

@@ -1,9 +1,14 @@
 import 'package:flutter/material.dart';
 
+import '../../about/external/data/Goal.dart';
 import 'NewCommitmentState.dart';
 
 class NewCommitment extends StatefulWidget {
-  const NewCommitment({super.key});
+  /// The goal this task is created inside; it can still be changed in the
+  /// form. Null starts the task loose.
+  final Goal? goal;
+
+  const NewCommitment({super.key, this.goal});
 
   @override
   State<NewCommitment> createState() => NewCommitmentState();