Implement Issue #2: Scheduling & Publishing

Replaces stub schedule CRUD with full shift template + instance system.

- DB: add shift_templates, shift_template_roles, shift_template_volunteers,
  shift_instances, shift_instance_volunteers tables
- schedule package: ShiftTemplate and ShiftInstance models with store
  (generate, publish/unpublish, per-instance edits, volunteer confirmation)
- API: shift-templates CRUD + shifts generate/publish/unpublish/update/confirm
- Notifications sent on publish (FR-S04), unpublish (FR-S05), instance edit
  (FR-S09), and volunteer added mid-month (FR-S10)
- Frontend: Schedules page with month navigation, template management,
  publish/unpublish controls, and per-shift edit/confirm
- Tests: Go handler tests (14 cases) + React tests (11 cases)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

web/src/api.ts

@@ -38,12 +38,26 @@ export const api = {
   resendInvite: (id: number) =>
     request<{ invite_token: string }>('POST', `/volunteers/${id}/invite`, {}),
 
-  // Schedules
-  listSchedules: () => request<Schedule[]>('GET', '/schedules'),
-  createSchedule: (data: CreateScheduleInput) => request<Schedule>('POST', '/schedules', data),
-  updateSchedule: (id: number, data: Partial<CreateScheduleInput>) =>
-    request<Schedule>('PUT', `/schedules/${id}`, data),
-  deleteSchedule: (id: number) => request<void>('DELETE', `/schedules/${id}`),
+  // Shift templates
+  listShiftTemplates: () => request<ShiftTemplate[]>('GET', '/shift-templates'),
+  createShiftTemplate: (data: CreateShiftTemplateInput) =>
+    request<ShiftTemplate>('POST', '/shift-templates', data),
+  updateShiftTemplate: (id: number, data: Partial<CreateShiftTemplateInput>) =>
+    request<ShiftTemplate>('PUT', `/shift-templates/${id}`, data),
+  deleteShiftTemplate: (id: number) => request<void>('DELETE', `/shift-templates/${id}`),
+
+  // Shift instances
+  listShifts: (year: number, month: number) =>
+    request<ShiftInstance[]>('GET', `/shifts?year=${year}&month=${month}`),
+  generateShifts: (year: number, month: number) =>
+    request<ShiftInstance[]>('POST', '/shifts/generate', { year, month }),
+  publishShifts: (year: number, month: number) =>
+    request<{ year: number; month: number }>('POST', '/shifts/publish', { year, month }),
+  unpublishShifts: (year: number, month: number) =>
+    request<{ year: number; month: number }>('POST', '/shifts/unpublish', { year, month }),
+  updateShift: (id: number, data: UpdateShiftInput) =>
+    request<ShiftInstance>('PUT', `/shifts/${id}`, data),
+  confirmShift: (id: number) => request<void>('POST', `/shifts/${id}/confirm`, {}),
 
   // Time off
   listTimeOff: () => request<TimeOffRequest[]>('GET', '/timeoff'),
@@ -104,23 +118,67 @@ export interface UpdateVolunteerInput {
   admin_notes?: string;
 }
 
-export interface Schedule {
+export interface TemplateRole {
+  id?: number;
+  template_id?: number;
+  role_name: string;
+  count: number;
+}
+
+export interface ShiftTemplate {
   id: number;
-  volunteer_id: number;
-  title: string;
-  starts_at: string;
-  ends_at: string;
-  notes?: string;
+  name: string;
+  day_of_week: number; // 0=Sun, 1=Mon, ..., 6=Sat
+  start_time: string;
+  end_time: string;
+  min_capacity: number;
+  max_capacity: number;
+  roles: TemplateRole[];
+  volunteer_ids: number[];
   created_at: string;
   updated_at: string;
 }
 
-export interface CreateScheduleInput {
-  volunteer_id?: number;
-  title: string;
-  starts_at: string;
-  ends_at: string;
-  notes?: string;
+export interface CreateShiftTemplateInput {
+  name: string;
+  day_of_week: number;
+  start_time: string;
+  end_time: string;
+  min_capacity: number;
+  max_capacity: number;
+  roles?: TemplateRole[];
+  volunteer_ids?: number[];
+}
+
+export interface InstanceVolunteer {
+  instance_id: number;
+  volunteer_id: number;
+  name: string;
+  confirmed: boolean;
+  confirmed_at?: string;
+}
+
+export interface ShiftInstance {
+  id: number;
+  template_id?: number;
+  name: string;
+  date: string; // "YYYY-MM-DD"
+  start_time: string;
+  end_time: string;
+  min_capacity: number;
+  max_capacity: number;
+  status: 'draft' | 'published';
+  year: number;
+  month: number;
+  volunteers: InstanceVolunteer[];
+  created_at: string;
+  updated_at: string;
+}
+
+export interface UpdateShiftInput {
+  volunteer_ids?: number[];
+  min_capacity?: number;
+  max_capacity?: number;
 }
 
 export interface TimeOffRequest {