Add address management features and improve validation

- Implement saveMyAddress mutation for updating user addresses.
- Enhance address validation schema with additional fields.
- Add error handling for location loading in LocationPicker.
- Update translations for loading errors in English and Amharic.
- Introduce phone number validation for Ethiopian formats.
- Refactor AddressFormContent to accommodate new address structure.

libs/ui/src/lib/input/phone.ts

@@ -0,0 +1,13 @@
+import { z } from 'zod';
+
+/** Accepts `09xxxxxxxx` or `+2519xxxxxxxx`; always yields `+2519xxxxxxxx`. */
+export const ethiopianPhone = z
+  .string()
+  .trim()
+  .transform((v) => (/^09\d{8}$/.test(v) ? `+251${v.slice(1)}` : v))
+  .refine((v) => /^\+2519\d{8}$/.test(v), {
+    message: 'Enter a valid phone number (+2519xxxxxxxx)',
+  });
+
+/** Same rules, but blank is allowed. */
+export const optionalEthiopianPhone = z.union([z.literal(''), ethiopianPhone]).optional();