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/utils/CommonUtils.dart

@@ -1,9 +1,13 @@
+import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:intl/intl.dart';
 
 import '../about/external/data/Commitment.dart';
+import '../about/external/data/RoutineStep.dart';
 import '../about/internal/application/CommitmentClass.dart';
+import '../about/internal/application/RoutineKind.dart';
 import '../about/internal/application/Standing.dart';
+import '../about/internal/application/StepMode.dart';
 import 'Colors.dart';
 
 /// Formatting and small shared derivations. Anything a screen would otherwise
@@ -186,3 +190,165 @@ String hourLabel(int hour) {
   }
   return "${hour - 12}pm";
 }
+
+Color kindColor(RoutineKind value) {
+  switch (value) {
+    case RoutineKind.Workout:
+      return colorKindWorkout;
+    case RoutineKind.Meditation:
+      return colorKindMeditation;
+    case RoutineKind.MustDo:
+      return colorKindMustDo;
+  }
+}
+
+Color kindBackground(RoutineKind value) {
+  switch (value) {
+    case RoutineKind.Workout:
+      return colorKindWorkoutBg;
+    case RoutineKind.Meditation:
+      return colorKindMeditationBg;
+    case RoutineKind.MustDo:
+      return colorKindMustDoBg;
+  }
+}
+
+/// The dark end of the kind's gradient — featured cards and the runner stage.
+Color kindDeep(RoutineKind value) {
+  switch (value) {
+    case RoutineKind.Workout:
+      return colorKindWorkoutDeep;
+    case RoutineKind.Meditation:
+      return colorKindMeditationDeep;
+    case RoutineKind.MustDo:
+      return colorKindMustDoDeep;
+  }
+}
+
+IconData kindIcon(RoutineKind value) {
+  switch (value) {
+    case RoutineKind.Workout:
+      return Icons.fitness_center_rounded;
+    case RoutineKind.Meditation:
+      return Icons.self_improvement_rounded;
+    case RoutineKind.MustDo:
+      return CupertinoIcons.checkmark_seal_fill;
+  }
+}
+
+IconData stepModeIcon(StepMode value) {
+  switch (value) {
+    case StepMode.Timed:
+      return CupertinoIcons.timer;
+    case StepMode.Reps:
+      return CupertinoIcons.repeat;
+    case StepMode.Check:
+      return CupertinoIcons.checkmark_square;
+  }
+}
+
+/// "45s", "2m", "1m 30s" — for step durations, where a clock face would be
+/// noise.
+String formatSeconds(int seconds) {
+  final int safe = seconds < 0 ? 0 : seconds;
+  if (safe < 60) {
+    return "${safe}s";
+  }
+  final int minutes = safe ~/ 60;
+  final int remainder = safe % 60;
+  if (remainder == 0) {
+    return "${minutes}m";
+  }
+  return "${minutes}m ${remainder}s";
+}
+
+/// "07:30" from minutes after midnight; empty when unset.
+String formatStartMinute(int minute) {
+  if (minute < 0) {
+    return "";
+  }
+  final int hour = minute ~/ 60;
+  final int rest = minute % 60;
+  return "${hour.toString().padLeft(2, '0')}:${rest.toString().padLeft(2, '0')}";
+}
+
+/// "M T W" style day initials for a 1..7 index.
+String weekdayInitial(int weekday) {
+  const List<String> initials = <String>["M", "T", "W", "T", "F", "S", "S"];
+  if (weekday < 1 || weekday > 7) {
+    return "";
+  }
+  return initials[weekday - 1];
+}
+
+/// "Weekdays", "Every day", "Mon · Wed · Fri" — a schedule read at a glance.
+String formatDays(List<int> days) {
+  if (days.isEmpty) {
+    return "On demand";
+  }
+  final List<int> sorted = List<int>.from(days)..sort();
+  if (sorted.length == 7) {
+    return "Every day";
+  }
+  if (sorted.length == 5 && sorted.every((day) => day <= 5)) {
+    return "Weekdays";
+  }
+  if (sorted.length == 2 && sorted.contains(6) && sorted.contains(7)) {
+    return "Weekends";
+  }
+  return sorted.map((day) => weekdayName(day).substring(0, 3)).join(" · ");
+}
+
+/// "4 × 12 reps · rest 90s" — one line that says what a step asks of you.
+String stepSummary(RoutineStep step) {
+  final List<String> parts = <String>[];
+
+  switch (step.mode) {
+    case StepMode.Timed:
+      parts.add(step.sets > 1
+          ? "${step.sets} × ${formatSeconds(step.timerSeconds)}"
+          : formatSeconds(step.timerSeconds));
+      break;
+    case StepMode.Reps:
+      parts.add("${step.sets} × ${step.reps} reps");
+      break;
+    case StepMode.Check:
+      parts.add(step.timerSeconds > 0
+          ? "Tick · ~${formatSeconds(step.timerSeconds)}"
+          : "Tick");
+      break;
+  }
+
+  if (step.restSeconds > 0) {
+    parts.add("rest ${formatSeconds(step.restSeconds)}");
+  }
+
+  return parts.join(" · ");
+}
+
+/// A goal's accent, falling back to ink when it has none.
+Color goalColor(String colourHex) {
+  if (colourHex.isEmpty) {
+    return colorPrimaryDark;
+  }
+  return getColorFromHex(colourHex);
+}
+
+/// "41 days left", "Due today", "12 days over" — the deadline read as a
+/// distance, which is what actually changes behaviour.
+String targetLabel(DateTime? target) {
+  if (target == null) {
+    return "";
+  }
+  final DateTime now = DateTime.now();
+  final DateTime today = DateTime(now.year, now.month, now.day);
+  final DateTime day = DateTime(target.year, target.month, target.day);
+  final int days = day.difference(today).inDays;
+  if (days == 0) {
+    return "Due today";
+  }
+  if (days < 0) {
+    return "${-days} day${days == -1 ? "" : "s"} over";
+  }
+  return "$days day${days == 1 ? "" : "s"} left";
+}