Update OKF docs bundle, README, and CLAUDE.md for today's features

Documents the shift planning and closure/payroll modules (new tables,
routes, stores), the dark redesign, and the docker-compose-broken-host
workaround. Adds CLAUDE.md pointing agents at docs/. Translates README to
English and keeps host-specific infrastructure details out of the repo.

docs/data-model/shift-slots.md

@@ -0,0 +1,51 @@
+---
+type: SQLite Table
+title: shift_slots
+description: Bookable shift slots (a date + time range + headcount capacity), generated from a weekly template or created ad hoc by the admin.
+resource: backend/src/db/index.ts
+tags: [data-model, sqlite, shift-planning]
+timestamp: 2026-08-16T00:00:00Z
+---
+
+# shift_slots
+
+# Schema
+
+| Column | Type | Description |
+|---|---|---|
+| `id` | INTEGER PK | autoincrement |
+| `date` | TEXT | `YYYY-MM-DD` |
+| `start_time` / `end_time` | TEXT | `HH:MM`; `end_time <= start_time` means the slot rolls past midnight |
+| `capacity` | INTEGER | headcount |
+| `status` | TEXT | `open` \| `full` \| `closed` — recomputed from capacity vs. approved signups on every change |
+| `note` | TEXT | free text |
+| `generated` | INTEGER | 1 if created by the weekly template, 0 if manually added by the admin |
+| `created_at` / `updated_at` | TEXT | ISO 8601 UTC |
+
+`UNIQUE (date, start_time, end_time)` — this is what makes template
+generation idempotent (`INSERT OR IGNORE`).
+
+# Weekly template
+
+`ensureSlotsForPeriod` (`backend/src/services/shiftPlanning.ts`) generates a
+whole calendar month lazily, the first time anyone (employee or admin)
+requests that period — not on a cron schedule. There's no scheduler in this
+app, and lazy + idempotent is simpler and just as reliable as the source
+system's Apps Script monthly trigger
+(`createShiftPlanningTrigger_` in `gscript/ShiftPlanningService.js`, which
+could only fire in a coarse hourly window).
+
+| Day | Slots |
+|---|---|
+| Sun–Thu | 18:00–23:00, capacity 1 |
+| Fri, Sat | 18:00–02:00, capacity 1 **and** 20:00–00:00, capacity 1 |
+
+The two Friday/Saturday slots deliberately overlap in time — a real
+scheduling choice from the source bistro (an early shift and a late shift),
+not a bug. It's also exactly what the collision test in
+`backend/src/services/shiftPlanning.test.ts` exercises.
+
+# Related
+
+- [shift_signups](./shift-signups.md)
+- [Shift planning API](/docs/api/shifts-routes.md)