feat(booking): day-grouped class list with honest capacity states

Class sessions rendered as a flat stack of tall cards below the
stepped picker, and a full session still offered "Book now" while
silently producing a waitlisted booking. Sessions now group by day
with compact timetable rows; empty sessions show Full and switch the
action to Join waitlist, and low capacity shows a warning count.

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project.md

@@ -116,6 +116,10 @@
   - `PUT /v1/catalog/class-templates/{id}` end-to-end: `UpdateClassTemplate` in both repositories, catalog service method sharing `validateClassTemplateInput` with create, route, OpenAPI path, regenerated client
   - classes tab template rows gained a pencil edit action that loads the template into the form; the submit button switches to save-changes with a cancel affordance
   - remaining: live staging validation
+- `[done/partial]` Milestone 18: Public class list polish
+  - class sessions on the public booking page are now grouped by day (localized weekday + date headers) with compact timetable-style rows instead of one tall card per session — consistent with the stepped appointment picker above
+  - capacity states read honestly: spots-left in success/warning tones, `Obsazeno`/`Full` when empty, and the action switches to `Na čekací listinu`/`Join waitlist` (previously a full session still said "Book now" while silently producing a waitlisted booking)
+  - remaining: live staging validation
 
 ## 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.