feat(web): add routine sync operations to platform-sync client

- SyncRoutineDTO + SyncRoutineStepDTO types
- pullRoutineDelta, pushRoutine, updateRemoteRoutine, deleteRemoteRoutine, batchUpsertRoutines
- routineToDTO / dtoToRoutinePatch conversion functions
- OfflineQueueItem now supports entityType (timer|routine)

web/src/lib/platform-sync.ts

@@ -3,6 +3,7 @@
 // Consumed by useSyncHook for React integration
 
 import type { Timer } from './timer-engine';
+import type { Routine, RoutineStep } from './routines';
 import { getAuthClient, PRODUCT_ID as _PRODUCT_ID } from './auth-api';
 
 // ── DTOs ──────────────────────────────────────────────────────
@@ -47,10 +48,37 @@ export interface BatchResult {
   errors: string[];
 }
 
+export interface SyncRoutineStepDTO {
+  id: string;
+  label: string;
+  durationMinutes: number;
+  transition: string;
+  customTransitionMinutes?: number;
+  notes?: string;
+  status: string;
+}
+
+export interface SyncRoutineDTO {
+  id: string;
+  name: string;
+  description?: string;
+  steps: SyncRoutineStepDTO[];
+  totalDurationMinutes: number;
+  status: string;
+  currentStepIndex: number;
+  isTemplate: boolean;
+  createdAt: string;
+  startedAt?: string;
+  completedAt?: string;
+  syncVersion: number;
+}
+
 export interface OfflineQueueItem {
   id: string;
   action: 'create' | 'update' | 'delete';
   timer?: SyncTimerDTO;
+  routine?: SyncRoutineDTO;
+  entityType: 'timer' | 'routine';
   enqueuedAt: number;
 }
 
@@ -182,6 +210,34 @@ export async function batchUpsert(
   return apiRequest<BatchResult>('/timers/batch', 'POST', { timers });
 }
 
+// ── Routine Sync Operations ──────────────────────────────────
+
+export async function pullRoutineDelta(since?: string): Promise<SyncRoutineDTO[]> {
+  const params = since ? `?since=${encodeURIComponent(since)}` : '';
+  return apiRequest<SyncRoutineDTO[]>(`/routines/sync${params}`, 'GET');
+}
+
+export async function pushRoutine(dto: SyncRoutineDTO): Promise<SyncRoutineDTO> {
+  return apiRequest<SyncRoutineDTO>('/routines', 'POST', dto);
+}
+
+export async function updateRemoteRoutine(
+  id: string,
+  updates: Partial<SyncRoutineDTO>
+): Promise<SyncRoutineDTO> {
+  return apiRequest<SyncRoutineDTO>(`/routines/${id}`, 'PUT', updates);
+}
+
+export async function deleteRemoteRoutine(id: string): Promise<void> {
+  return apiRequest<void>(`/routines/${id}`, 'DELETE');
+}
+
+export async function batchUpsertRoutines(
+  routines: SyncRoutineDTO[]
+): Promise<BatchResult> {
+  return apiRequest<BatchResult>('/routines/batch', 'POST', { routines });
+}
+
 // ── Offline Queue ─────────────────────────────────────────────
 
 export function loadOfflineQueue(): OfflineQueueItem[] {
@@ -208,6 +264,7 @@ export function enqueueChange(
     id: timer.id,
     action,
     timer: action !== 'delete' ? timerToDTO(timer) : undefined,
+    entityType: 'timer',
     enqueuedAt: Date.now(),
   });
   saveOfflineQueue(queue);
@@ -215,7 +272,7 @@ export function enqueueChange(
 
 export function enqueueDeleteChange(timerId: string): void {
   const queue = loadOfflineQueue().filter((item) => item.id !== timerId);
-  queue.push({ id: timerId, action: 'delete', enqueuedAt: Date.now() });
+  queue.push({ id: timerId, action: 'delete', entityType: 'timer', enqueuedAt: Date.now() });
   saveOfflineQueue(queue);
 }
 
@@ -316,6 +373,59 @@ export function timerToDTO(timer: Timer): SyncTimerDTO {
   };
 }
 
+// ── Routine DTO Conversion ───────────────────────────────────
+
+export function routineToDTO(routine: Routine): SyncRoutineDTO {
+  return {
+    id: routine.id,
+    name: routine.name,
+    description: routine.description,
+    steps: routine.steps.map((s) => ({
+      id: s.id,
+      label: s.label,
+      durationMinutes: s.durationMinutes,
+      transition: s.transition,
+      customTransitionMinutes: s.customTransitionMinutes,
+      notes: s.notes,
+      status: s.status,
+    })),
+    totalDurationMinutes: routine.totalDurationMinutes,
+    status: routine.status,
+    currentStepIndex: routine.currentStepIndex,
+    isTemplate: routine.isTemplate,
+    createdAt: new Date(routine.createdAt).toISOString(),
+    startedAt: routine.startedAt ? new Date(routine.startedAt).toISOString() : undefined,
+    completedAt: routine.completedAt ? new Date(routine.completedAt).toISOString() : undefined,
+    syncVersion: 1,
+  };
+}
+
+export function dtoToRoutinePatch(dto: SyncRoutineDTO): Partial<Routine> {
+  return {
+    id: dto.id,
+    name: dto.name,
+    description: dto.description,
+    steps: dto.steps.map((s) => ({
+      id: s.id,
+      label: s.label,
+      durationMinutes: s.durationMinutes,
+      transition: s.transition as RoutineStep['transition'],
+      customTransitionMinutes: s.customTransitionMinutes ?? 0,
+      notes: s.notes,
+      status: s.status as RoutineStep['status'],
+      startedAt: null,
+      completedAt: null,
+    })),
+    totalDurationMinutes: dto.totalDurationMinutes,
+    status: dto.status as Routine['status'],
+    currentStepIndex: dto.currentStepIndex,
+    isTemplate: dto.isTemplate,
+    createdAt: new Date(dto.createdAt).getTime(),
+    startedAt: dto.startedAt ? new Date(dto.startedAt).getTime() : null,
+    completedAt: dto.completedAt ? new Date(dto.completedAt).getTime() : null,
+  };
+}
+
 export function dtoToTimerPatch(dto: SyncTimerDTO): Partial<Timer> {
   return {
     id: dto.id,