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/designs/GoalPicker.dart

@@ -0,0 +1,127 @@
+import 'package:flutter/cupertino.dart';
+import 'package:flutter/material.dart';
+
+import '../about/external/data/Goal.dart';
+import '../about/internal/application/TextType.dart';
+import '../utils/Colors.dart';
+import '../utils/CommonUtils.dart';
+import 'text/Text.dart';
+
+/// The goal chooser, shared by the task form and the routine builder. Opened
+/// only once the goals have been loaded — `selectField` loads on tap.
+///
+/// Resolves to the chosen goal, to a bare `Goal()` (no id) for "no goal", or
+/// to null when dismissed without a choice.
+Future<Goal?> showGoalPicker(
+  BuildContext context,
+  List<Goal> goals, {
+  String? selectedId,
+}) {
+  return showModalBottomSheet<Goal>(
+    context: context,
+    isScrollControlled: true,
+    backgroundColor: Colors.transparent,
+    barrierColor: colorBlack.withValues(alpha: 0.55),
+    builder: (BuildContext sheetContext) {
+      final List<Goal> active = goals.where((goal) => !goal.archived).toList();
+
+      return Container(
+        constraints: BoxConstraints(
+          maxHeight: MediaQuery.of(sheetContext).size.height * 0.75,
+        ),
+        decoration: const BoxDecoration(
+          color: colorSheetBackground,
+          borderRadius: BorderRadius.only(
+            topLeft: Radius.circular(28),
+            topRight: Radius.circular(28),
+          ),
+        ),
+        child: ListView(
+          shrinkWrap: true,
+          padding: const EdgeInsets.fromLTRB(24, 24, 24, 32),
+          children: [
+            text("BELONGS TO", 9, TextType.Bold,
+                color: colorGrey2, letterSpacing: 1.2),
+            const SizedBox(height: 8),
+            text("Which goal is this for?", 24, TextType.Light,
+                color: colorPrimaryDark),
+            const SizedBox(height: 18),
+            _goalOption(
+              sheetContext,
+              Goal(),
+              "No goal",
+              "Stands on its own",
+              colorGrey,
+              selectedId == null,
+            ),
+            ...active.map((goal) => _goalOption(
+                  sheetContext,
+                  goal,
+                  goal.title,
+                  goal.targetDate == null
+                      ? "${goal.remainingTasks} open"
+                      : "${goal.remainingTasks} open · ${targetLabel(goal.targetDate)}",
+                  goalColor(goal.colourHex),
+                  goal.id == selectedId,
+                )),
+            if (active.isEmpty) ...[
+              const SizedBox(height: 8),
+              text("No goals yet. Create one from the Goals screen.", 12,
+                  TextType.Regular,
+                  color: colorGrey2),
+            ],
+          ],
+        ),
+      );
+    },
+  );
+}
+
+Widget _goalOption(
+  BuildContext sheetContext,
+  Goal goal,
+  String title,
+  String caption,
+  Color accent,
+  bool selected,
+) {
+  return GestureDetector(
+    onTap: () => Navigator.pop(sheetContext, goal),
+    behavior: HitTestBehavior.opaque,
+    child: Container(
+      margin: const EdgeInsets.only(bottom: 8),
+      padding: const EdgeInsets.fromLTRB(14, 13, 14, 13),
+      decoration: BoxDecoration(
+        color: colorWhite,
+        borderRadius: BorderRadius.circular(14),
+        border: Border.all(
+          color: selected ? accent.withValues(alpha: 0.5) : colorBorder,
+          width: selected ? 1.5 : 1,
+        ),
+      ),
+      child: Row(
+        children: [
+          Container(
+            width: 12,
+            height: 12,
+            decoration: BoxDecoration(color: accent, shape: BoxShape.circle),
+          ),
+          const SizedBox(width: 14),
+          Expanded(
+            child: Column(
+              crossAxisAlignment: CrossAxisAlignment.start,
+              mainAxisSize: MainAxisSize.min,
+              children: [
+                text(title, 14, TextType.Medium, color: colorPrimaryDark),
+                const SizedBox(height: 3),
+                text(caption, 11, TextType.Regular, color: colorGrey2),
+              ],
+            ),
+          ),
+          if (selected)
+            Icon(CupertinoIcons.checkmark_alt, size: 17, color: accent),
+        ],
+      ),
+    ),
+  );
+}