Add lessons module, rate cycles, EC2 deploy scripts, and help content

- Lessons module: lesson types, instructors, schedule slots, enrollments,
  sessions (list + week grid view), lesson plans, grading scales, templates
- Rate cycles: replace monthly_rate with billing_interval + billing_unit on
  enrollments; add weekly/monthly/quarterly rate presets to lesson types and
  schedule slots with auto-fill on enrollment form
- Member detail page: tabbed layout for details, identity documents, enrollments
- Sessions week view: custom 7-column grid replacing react-big-calendar
- Music store seed: instructors, lesson types, slots, enrollments, sessions,
  grading scale, lesson plan template
- Scrollbar styling: themed to match sidebar/app palette
- deploy/: EC2 setup and redeploy scripts, nginx config, systemd service
- Help: add Lessons category (overview, types, instructors, slots, enrollments,
  sessions, plans/grading); collapsible sidebar with independent scroll;
  remove POS/accounting references from docs

packages/admin/src/components/lessons/schedule-slot-form.tsx

@@ -0,0 +1,124 @@
+import { useForm } from 'react-hook-form'
+import { Button } from '@/components/ui/button'
+import { Input } from '@/components/ui/input'
+import { Label } from '@/components/ui/label'
+import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from '@/components/ui/select'
+import type { LessonType, ScheduleSlot } from '@/types/lesson'
+
+const DAYS = ['Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday']
+
+interface Props {
+  lessonTypes: LessonType[]
+  defaultValues?: Partial<ScheduleSlot>
+  onSubmit: (data: Record<string, unknown>) => void
+  loading?: boolean
+}
+
+export function ScheduleSlotForm({ lessonTypes, defaultValues, onSubmit, loading }: Props) {
+  const { register, handleSubmit, setValue, watch } = useForm({
+    defaultValues: {
+      dayOfWeek: String(defaultValues?.dayOfWeek ?? 1),
+      startTime: defaultValues?.startTime ?? '',
+      lessonTypeId: defaultValues?.lessonTypeId ?? '',
+      room: defaultValues?.room ?? '',
+      maxStudents: String(defaultValues?.maxStudents ?? 1),
+      rateWeekly: defaultValues?.rateWeekly ?? '',
+      rateMonthly: defaultValues?.rateMonthly ?? '',
+      rateQuarterly: defaultValues?.rateQuarterly ?? '',
+    },
+  })
+
+  const dayOfWeek = watch('dayOfWeek')
+  const lessonTypeId = watch('lessonTypeId')
+
+  function handleFormSubmit(data: {
+    dayOfWeek: string
+    startTime: string
+    lessonTypeId: string
+    room: string
+    maxStudents: string
+    rateWeekly: string
+    rateMonthly: string
+    rateQuarterly: string
+  }) {
+    onSubmit({
+      dayOfWeek: Number(data.dayOfWeek),
+      startTime: data.startTime,
+      lessonTypeId: data.lessonTypeId,
+      room: data.room || undefined,
+      maxStudents: Number(data.maxStudents) || 1,
+      rateWeekly: data.rateWeekly || undefined,
+      rateMonthly: data.rateMonthly || undefined,
+      rateQuarterly: data.rateQuarterly || undefined,
+    })
+  }
+
+  return (
+    <form onSubmit={handleSubmit(handleFormSubmit)} className="space-y-4">
+      <div className="grid grid-cols-2 gap-4">
+        <div className="space-y-2">
+          <Label>Day *</Label>
+          <Select value={dayOfWeek} onValueChange={(v) => setValue('dayOfWeek', v)}>
+            <SelectTrigger>
+              <SelectValue />
+            </SelectTrigger>
+            <SelectContent>
+              {DAYS.map((day, i) => (
+                <SelectItem key={i} value={String(i)}>{day}</SelectItem>
+              ))}
+            </SelectContent>
+          </Select>
+        </div>
+        <div className="space-y-2">
+          <Label htmlFor="slot-time">Start Time *</Label>
+          <Input id="slot-time" type="time" {...register('startTime')} required />
+        </div>
+      </div>
+      <div className="space-y-2">
+        <Label>Lesson Type *</Label>
+        <Select value={lessonTypeId} onValueChange={(v) => setValue('lessonTypeId', v)}>
+          <SelectTrigger>
+            <SelectValue placeholder="Select lesson type..." />
+          </SelectTrigger>
+          <SelectContent>
+            {lessonTypes.map((lt) => (
+              <SelectItem key={lt.id} value={lt.id}>
+                {lt.name} ({lt.durationMinutes} min)
+              </SelectItem>
+            ))}
+          </SelectContent>
+        </Select>
+      </div>
+      <div className="grid grid-cols-2 gap-4">
+        <div className="space-y-2">
+          <Label htmlFor="slot-room">Room</Label>
+          <Input id="slot-room" {...register('room')} placeholder="e.g. Studio A" />
+        </div>
+        <div className="space-y-2">
+          <Label htmlFor="slot-max">Max Students</Label>
+          <Input id="slot-max" type="number" min={1} {...register('maxStudents')} />
+        </div>
+      </div>
+      <div>
+        <Label className="block mb-2">Instructor Rates (override lesson type defaults)</Label>
+        <div className="grid grid-cols-3 gap-3">
+          <div className="space-y-1">
+            <Label htmlFor="slot-rate-weekly" className="text-xs text-muted-foreground">Weekly</Label>
+            <Input id="slot-rate-weekly" type="number" step="0.01" min="0" {...register('rateWeekly')} placeholder="—" />
+          </div>
+          <div className="space-y-1">
+            <Label htmlFor="slot-rate-monthly" className="text-xs text-muted-foreground">Monthly</Label>
+            <Input id="slot-rate-monthly" type="number" step="0.01" min="0" {...register('rateMonthly')} placeholder="—" />
+          </div>
+          <div className="space-y-1">
+            <Label htmlFor="slot-rate-quarterly" className="text-xs text-muted-foreground">Quarterly</Label>
+            <Input id="slot-rate-quarterly" type="number" step="0.01" min="0" {...register('rateQuarterly')} placeholder="—" />
+          </div>
+        </div>
+      </div>
+      <Button type="submit" disabled={loading || !lessonTypeId} className="w-full">
+        {loading ? 'Saving...' : defaultValues?.id ? 'Save Changes' : 'Add Slot'}
+      </Button>
+    </form>
+  )
+}