feat(export): CSV export for bookings and customers

GET /v1/export/bookings.csv (optional from/to bounds) and
/v1/export/customers.csv — UTF-8 with BOM for Excel, labels resolved
at export time, buffered responses so auth failures stay JSON.
Export buttons on the bookings and customers pages.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

packages/api-client/src/generated/types.ts

@@ -664,6 +664,46 @@ export interface paths {
         patch?: never;
         trace?: never;
     };
+    "/v1/export/bookings.csv": {
+        parameters: {
+            query?: never;
+            header?: never;
+            path?: never;
+            cookie?: never;
+        };
+        /**
+         * Export tenant bookings as CSV
+         * @description Full booking export for accounting and backup — UTF-8 with BOM so Czech diacritics open correctly in Excel. Optional `from`/`to` (YYYY-MM-DD) bounds the export window; `to` is inclusive.
+         */
+        get: operations["exportBookingsCsv"];
+        put?: never;
+        post?: never;
+        delete?: never;
+        options?: never;
+        head?: never;
+        patch?: never;
+        trace?: never;
+    };
+    "/v1/export/customers.csv": {
+        parameters: {
+            query?: never;
+            header?: never;
+            path?: never;
+            cookie?: never;
+        };
+        /**
+         * Export tenant customers as CSV
+         * @description Full customer list export — UTF-8 with BOM for Excel.
+         */
+        get: operations["exportCustomersCsv"];
+        put?: never;
+        post?: never;
+        delete?: never;
+        options?: never;
+        head?: never;
+        patch?: never;
+        trace?: never;
+    };
     "/v1/internal/jobs/reminders/dispatch": {
         parameters: {
             query?: never;
@@ -3359,6 +3399,63 @@ export interface operations {
             };
         };
     };
+    exportBookingsCsv: {
+        parameters: {
+            query?: {
+                from?: string;
+                to?: string;
+            };
+            header?: never;
+            path?: never;
+            cookie?: never;
+        };
+        requestBody?: never;
+        responses: {
+            /** @description CSV file download */
+            200: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "text/csv": string;
+                };
+            };
+            /** @description Tenant membership not found */
+            404: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content?: never;
+            };
+        };
+    };
+    exportCustomersCsv: {
+        parameters: {
+            query?: never;
+            header?: never;
+            path?: never;
+            cookie?: never;
+        };
+        requestBody?: never;
+        responses: {
+            /** @description CSV file download */
+            200: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "text/csv": string;
+                };
+            };
+            /** @description Tenant membership not found */
+            404: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content?: never;
+            };
+        };
+    };
     dispatchReminderJobs: {
         parameters: {
             query?: never;