feat(waitlist): queue position on the customer manage page

A waitlisted customer saw only a bare status — worse, the badge fell
back to "Pending" for both waitlisted and cancelled states. The view
now carries a 1-based waitlistPosition (earlier-created waitlisted
bookings on the session + 1) and the page renders a warning-tone
notice with the queue spot and auto-promotion explanation, in CS/EN.
Also fixed the badge's nonexistent --danger-soft/--warning-soft tokens.

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project.md

@@ -107,6 +107,11 @@
   - `sms.Service.SendMessage` still enforces enabled/plan/monthly-limit and logs usage, so SMS reminders inherit metering and billing automatically; missing provider config or phone marks the job `failed` with a delivery-log reason
   - reminder lifecycle work from milestone 13 applies per-booking, so cancel/reschedule clears and re-arms both channels
   - remaining: live staging validation against a real SMS Manager key
+- `[done/partial]` Milestone 16: Waitlist position display
+  - `GetWaitlistPosition` repository method (pgx + memory) returns the 1-based queue spot: count of earlier-created waitlisted bookings on the same session + 1
+  - `CustomerBookingView` carries `waitlistPosition` for waitlisted class bookings; the manage page now shows a proper status badge for `waitlisted`/`cancelled` (previously both rendered as "Pending") plus a notice with the queue position and the auto-promotion explanation, in CS and EN
+  - fixed invalid token names along the way (`--danger-soft`/`--warning-soft` do not exist; `--error-subtle`/`--warning-subtle` do)
+  - remaining: live staging validation; manual waitlist promotion controls are still not exposed
 
 ## Overview
 Bookra is a Czech-first booking SaaS for small local service businesses. It targets salons, massage therapists, small clinics, repair shops, and small studios/clubs that need a simple public booking flow, internal schedule management, reminders, and basic business reporting without becoming a full ERP.