feat(services): customer-linked services CRUD module

Same pattern as customers. Each service belongs to one customer (FK), has
unit price (TRY), billing period (monthly/yearly/onetime), and recurring
flag.

- lib/validation/services.ts: Zod schema with TRY price coercion (accepts
  comma decimal), enum billing period, recurring boolean coercion.
- lib/appwrite/service-actions.ts: createServiceAction, updateServiceAction,
  deleteServiceAction. Same tenant guard, audit log, team-scoped row perms.
- lib/appwrite/service-queries.ts: listServices, listServicesByCustomer.
- lib/format.ts: formatTRY (Intl.NumberFormat tr-TR), formatDate/DateTime,
  BILLING_PERIOD_LABEL mapping (Aylık/Yıllık/Tek seferlik).
- /services page (server): joins services with customer names via
  in-memory map.
- ServicesClient: TanStack table with global filter (name/customer/desc),
  Repeat icon next to recurring badges, formatted TRY column.
- ServiceFormSheet: customer dropdown (disabled if no customers exist),
  unit price + billing period + recurring switch.
- DeleteServiceDialog: same destructive confirmation pattern.

Empty state on /services CTA's user back to add a customer first if none
exist.

src/lib/validation/services.ts

@@ -0,0 +1,23 @@
+import { z } from "zod";
+
+export const serviceSchema = z.object({
+  customerId: z.string().min(1, "Müşteri seçin."),
+  name: z.string().trim().min(1, "Hizmet adı zorunlu.").max(255),
+  description: z
+    .string()
+    .trim()
+    .max(2000)
+    .optional()
+    .transform((v) => (v ? v : undefined)),
+  unitPrice: z
+    .union([z.number(), z.string()])
+    .transform((v) => (typeof v === "string" ? Number(v.replace(",", ".")) : v))
+    .pipe(z.number().nonnegative("Negatif olamaz.")),
+  recurring: z
+    .union([z.boolean(), z.literal("on"), z.literal(""), z.undefined()])
+    .transform((v) => v === true || v === "on")
+    .optional(),
+  billingPeriod: z.enum(["monthly", "yearly", "onetime"]).optional().default("onetime"),
+});
+
+export type ServiceInput = z.infer<typeof serviceSchema>;