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/goal/GoalEditor.dart

@@ -0,0 +1,16 @@
+import 'package:flutter/material.dart';
+
+import '../../about/external/data/Goal.dart';
+import 'GoalEditorState.dart';
+
+/// Create or edit a goal. Pops the saved [Goal], or `"archived"` when the goal
+/// was archived, so a detail screen underneath knows to close as well.
+class GoalEditor extends StatefulWidget {
+  /// The goal being edited; null creates a new one.
+  final Goal? goal;
+
+  const GoalEditor({super.key, this.goal});
+
+  @override
+  State<GoalEditor> createState() => GoalEditorState();
+}