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/weekly-slot-grid.tsx

@@ -0,0 +1,87 @@
+import { Badge } from '@/components/ui/badge'
+import { Button } from '@/components/ui/button'
+import { Pencil, Trash2 } from 'lucide-react'
+import type { ScheduleSlot, LessonType } from '@/types/lesson'
+
+const DAYS = ['Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat']
+
+interface Props {
+  slots: ScheduleSlot[]
+  lessonTypes: LessonType[]
+  onEdit: (slot: ScheduleSlot) => void
+  onDelete: (slot: ScheduleSlot) => void
+}
+
+function formatTime(t: string) {
+  const [h, m] = t.split(':').map(Number)
+  const ampm = h >= 12 ? 'PM' : 'AM'
+  const hour = h % 12 || 12
+  return `${hour}:${String(m).padStart(2, '0')} ${ampm}`
+}
+
+export function WeeklySlotGrid({ slots, lessonTypes, onEdit, onDelete }: Props) {
+  const ltMap = new Map(lessonTypes.map((lt) => [lt.id, lt]))
+
+  const slotsByDay = DAYS.map((_, day) =>
+    slots.filter((s) => s.dayOfWeek === day).sort((a, b) => a.startTime.localeCompare(b.startTime)),
+  )
+
+  const hasAny = slots.length > 0
+
+  return (
+    <div className="grid grid-cols-7 gap-2">
+      {DAYS.map((day, idx) => (
+        <div key={day} className="min-h-[120px]">
+          <div className="text-xs font-semibold text-muted-foreground uppercase tracking-wide text-center mb-2 py-1 border-b">
+            {day}
+          </div>
+          <div className="space-y-2">
+            {slotsByDay[idx].map((slot) => {
+              const lt = ltMap.get(slot.lessonTypeId)
+              return (
+                <div
+                  key={slot.id}
+                  className="bg-sidebar-accent rounded-md p-2 text-xs group relative"
+                >
+                  <div className="font-medium">{formatTime(slot.startTime)}</div>
+                  <div className="text-muted-foreground truncate">{lt?.name ?? 'Unknown'}</div>
+                  {slot.room && <div className="text-muted-foreground">{slot.room}</div>}
+                  {lt && (
+                    <Badge variant="outline" className="mt-1 text-[10px] py-0">
+                      {lt.lessonFormat}
+                    </Badge>
+                  )}
+                  <div className="absolute top-1 right-1 hidden group-hover:flex gap-1">
+                    <Button
+                      variant="ghost"
+                      size="icon"
+                      className="h-5 w-5"
+                      onClick={() => onEdit(slot)}
+                      title="Edit"
+                    >
+                      <Pencil className="h-3 w-3" />
+                    </Button>
+                    <Button
+                      variant="ghost"
+                      size="icon"
+                      className="h-5 w-5"
+                      onClick={() => onDelete(slot)}
+                      title="Delete"
+                    >
+                      <Trash2 className="h-3 w-3 text-destructive" />
+                    </Button>
+                  </div>
+                </div>
+              )
+            })}
+          </div>
+        </div>
+      ))}
+      {!hasAny && (
+        <div className="col-span-7 text-center text-sm text-muted-foreground py-8">
+          No schedule slots yet — add one to get started.
+        </div>
+      )}
+    </div>
+  )
+}