feat(intake): structured per-service intake questions

Services declare up to 8 intake fields (text/yesno, required) stored
as JSONB; shared/intake.go is the single normalization point — slug
keys, label/dup/unknown-key rules, yes/no canonicalization. Booking
create validates answers against the service declaration (missing
required -> 400), unknown keys are dropped before persist.

Answers surface on UpcomingBooking and CustomerBookingView; the
services page gains a compact editor and the public form renders
declared questions under contact details. Verified live end-to-end.

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

@@ -2044,6 +2044,21 @@ components:
           type: array
           items:
             $ref: "#/components/schemas/PublicStaff"
+    IntakeField:
+      type: object
+      required: [key, label, type]
+      properties:
+        key:
+          type: string
+          description: Slug key (lowercase alnum + underscore); JSON key in booking intake answers
+        label:
+          type: string
+          description: Customer-facing question text
+        type:
+          type: string
+          enum: [text, yesno]
+        required:
+          type: boolean
     PublicService:
       type: object
       required: [id, name, durationMinutes, priceCents]
@@ -2057,6 +2072,10 @@ components:
           type: integer
         priceCents:
           type: integer
+        intakeFields:
+          type: array
+          items:
+            $ref: "#/components/schemas/IntakeField"
     PublicStaff:
       type: object
       required: [id, displayName]
@@ -2094,6 +2113,11 @@ components:
           format: email
         notes:
           type: string
+        intake:
+          type: object
+          additionalProperties:
+            type: string
+          description: Structured intake answers keyed by the service's declared intakeFields keys
         startsAt:
           type: string
           format: date-time
@@ -2190,6 +2214,11 @@ components:
           type: string
         notes:
           type: string
+        intake:
+          type: object
+          additionalProperties:
+            type: string
+          description: Structured intake answers keyed by the service's declared intakeFields keys
         classSessionId:
           type: string
           format: uuid
@@ -2233,6 +2262,10 @@ components:
           type: string
         notes:
           type: string
+        intake:
+          type: object
+          additionalProperties:
+            type: string
         waitlistPosition:
           type: integer
           description: 1-based queue spot for waitlisted class bookings; absent otherwise
@@ -2619,6 +2652,11 @@ components:
         priceCents:
           type: integer
           description: Price in the tenant's currency minor units
+        intakeFields:
+          type: array
+          items:
+            $ref: "#/components/schemas/IntakeField"
+          description: Structured intake questions asked at booking time (max 8)
         createdAt:
           type: string
           format: date-time
@@ -2636,6 +2674,10 @@ components:
           type: integer
         priceCents:
           type: integer
+        intakeFields:
+          type: array
+          items:
+            $ref: "#/components/schemas/IntakeField"
     StaffMember:
       type: object
       required: [id, tenantId, displayName, active]