feat(classes): weekly recurring schedules with lazy session materialization

class_schedules rules generate concrete session rows for a rolling 28-day
horizon — no cron; materialize runs idempotently on dashboard and public
reads via a partial unique index on (schedule_id, starts_at). Rule delete
stops future sessions; existing sessions keep bookings and overrides.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

apps/backend/openapi/bookra.openapi.yaml

@@ -1350,6 +1350,68 @@ paths:
                 $ref: "#/components/schemas/SessionRoster"
         "404":
           description: Class session not found
+  /v1/catalog/class-schedules:
+    get:
+      tags: [Catalog]
+      operationId: listClassSchedules
+      security:
+        - bearerAuth: []
+      summary: Weekly recurring rules for class sessions
+      description: >
+        Each rule materializes concrete class_sessions for a rolling 28-day
+        horizon in the tenant timezone. Sessions are written idempotently on
+        read (list class sessions or public availability), so no background
+        job is needed. Deleting a rule stops future materialization; sessions
+        already created stay in place and keep their bookings.
+      responses:
+        "200":
+          description: Recurring class schedules
+          content:
+            application/json:
+              schema:
+                type: array
+                items:
+                  $ref: "#/components/schemas/ClassSchedule"
+    post:
+      tags: [Catalog]
+      operationId: createClassSchedule
+      security:
+        - bearerAuth: []
+      requestBody:
+        required: true
+        content:
+          application/json:
+            schema:
+              $ref: "#/components/schemas/CreateClassScheduleRequest"
+      responses:
+        "201":
+          description: Class schedule created (sessions materialized immediately)
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/ClassSchedule"
+        "400":
+          description: Invalid request
+        "404":
+          description: Template or location not found
+  /v1/catalog/class-schedules/{scheduleID}:
+    delete:
+      tags: [Catalog]
+      operationId: deleteClassSchedule
+      security:
+        - bearerAuth: []
+      parameters:
+        - in: path
+          name: scheduleID
+          required: true
+          schema:
+            type: string
+            format: uuid
+      responses:
+        "200":
+          description: Class schedule deleted
+        "404":
+          description: Class schedule not found
   # ---------------- Calendar ----------------
   /v1/calendar/feed:
     get:
@@ -2755,6 +2817,10 @@ components:
           type: integer
         waitlistCount:
           type: integer
+        scheduleId:
+          type: string
+          format: uuid
+          description: Recurring rule that generated this session; absent for manual sessions
     SessionRosterEntry:
       type: object
       required: [bookingId, reference, customerName, customerEmail, status, createdAt]
@@ -2825,6 +2891,54 @@ components:
           format: date-time
         capacity:
           type: integer
+    ClassSchedule:
+      type: object
+      required: [id, tenantId, templateId, templateTitle, dayOfWeek, startsLocal, active]
+      properties:
+        id:
+          type: string
+          format: uuid
+        tenantId:
+          type: string
+          format: uuid
+        templateId:
+          type: string
+          format: uuid
+        templateTitle:
+          type: string
+        locationId:
+          type: string
+          format: uuid
+        locationName:
+          type: string
+        dayOfWeek:
+          type: integer
+          minimum: 0
+          maximum: 6
+          description: 0=Sunday ... 6=Saturday
+        startsLocal:
+          type: string
+          description: Tenant-local start time, HH:MM:SS
+        active:
+          type: boolean
+    CreateClassScheduleRequest:
+      type: object
+      required: [templateId, dayOfWeek, startsLocal]
+      properties:
+        templateId:
+          type: string
+          format: uuid
+        locationId:
+          type: string
+          format: uuid
+        dayOfWeek:
+          type: integer
+          minimum: 0
+          maximum: 6
+          description: 0=Sunday ... 6=Saturday
+        startsLocal:
+          type: string
+          description: Tenant-local start time, HH:MM
     PlanEntitlements:
       type: object
       required: [maxLocations, maxStaff, emailReminders, advancedReporting, widgetEmbedding, umamiTracking]