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/api/closure-routes.md

@@ -0,0 +1,39 @@
+---
+type: API Endpoint
+title: Closure routes (employee)
+description: GET /api/closure, POST /api/closure/confirm — the employee's own month-end confirmation.
+resource: backend/src/routes/closure.ts
+tags: [api, payroll]
+timestamp: 2026-08-16T00:00:00Z
+---
+
+# Closure routes (employee)
+
+Mounted at `/api/closure`. Every route requires `requireAuth` +
+`requireEmployee`.
+
+# Examples
+
+```
+GET /api/closure?period=YYYY-MM
+200 -> { "closure": MonthClosure, "summary": ClosureSummary }
+```
+Lazily creates the closure row (`waiting_employee`) the first time this
+period is opened. `summary` (`worked_minutes`, `shift_count`,
+`earned_estimate`) is always computed live from
+[attendance_events](/docs/data-model/attendance-events.md) — never stored
+on the closure row itself.
+
+```
+POST /api/closure/confirm
+Body: { "period": "YYYY-MM" }
+200 -> { "ok": true }
+400 -> "V tomto měsíci máš stále otevřenou směnu." (open shift blocks it)
+     | "Docházka je už uzamčena." (already locked)
+```
+
+# Related
+
+- [month_closures](/docs/data-model/month-closures.md)
+- [Admin routes](./admin-routes.md) — lock/reopen, tips/bonus adjustments, mark paid
+- [Frontend stores](/docs/frontend/stores.md) — `closureStore`