feat(api): add staff order detail and compliance eligibility

docs/BACKEND/API_GUIDES/V2/mobile-coding-agent-spec.md

@@ -23,7 +23,7 @@ Supporting docs:
 - Send `Idempotency-Key` on every write route.
 - Treat `order`, `shift`, `shiftRole`, and `assignment` as different objects.
 - For staff shift applications, `roleId` must come from the response of `GET /staff/shifts/open`.
-- For staff order booking, `roleId` must come from the response of `GET /staff/orders/available`.
+- For staff order booking, `roleId` must come from the response of `GET /staff/orders/:orderId`.
 - Treat API timestamp fields as UTC and convert them to local time in the app.
 
 ## 2) What is implemented now
@@ -235,14 +235,17 @@ Important:
 ### Find shifts
 
 - `GET /staff/orders/available`
+- `GET /staff/orders/:orderId`
 - `POST /staff/orders/:orderId/book`
 - `GET /staff/shifts/open`
 - `POST /staff/shifts/:shiftId/apply`
 
 Rule:
 
-- use `roleId` from the order-available response when booking an order
+- use `GET /staff/orders/:orderId` as the source of truth for the order details page
+- use `roleId` from the order-detail response when booking an order
 - that `roleId` is the role catalog id for the grouped order booking flow
+- if order booking returns `422`, render `details.blockers` and keep the worker on the order details page
 - use `roleId` from the open-shifts response only for shift-level apply
 - that `roleId` is the concrete `shift_roles.id`
 
@@ -260,6 +263,7 @@ Rule:
 
 Staff shift detail and list rules:
 
+- `GET /staff/orders/:orderId` returns the worker booking detail contract with `schedule`, `location`, `pay`, `staffing`, `managers`, and `eligibility`
 - assigned shifts include `clientName`, `hourlyRate`, `totalRate`, `startTime`, `endTime`
 - shift detail includes `clientName`, `latitude`, `longitude`, `hourlyRate`, `totalRate`
 - completed shifts include `date`, `clientName`, `startTime`, `endTime`, `hourlyRate`, `totalRate`