feat: implement user & family group management tRPC router

- Add user router with me/update/delete procedures (protected)
- Add family router with listMembers/invite/remove/updateRole procedures
- Create user service layer (getUserById, updateUser, deleteUser)
- Create family service layer (getFamilyGroup, inviteMember, removeMember, updateMemberRole, transferOwnership)
- Add Valibot input schemas for all procedures
- Add invitations table with status tracking and expiration
- Add deletedAt column to users table (soft-delete)
- Wire user router into app root router
- Write unit tests for service functions and tRPC procedures
- Update schema tests for new table/columns

web/src/server/api/schemas/user.ts

@@ -0,0 +1,21 @@
+import { object, string, email, minLength, optional, picklist } from "valibot";
+
+export const UpdateUserSchema = object({
+  name: optional(string([minLength(1)])),
+  email: optional(string([email()])),
+  image: optional(string()),
+});
+
+export const InviteMemberSchema = object({
+  email: string([email()]),
+  role: optional(picklist(["admin", "member"]), "member"),
+});
+
+export const RemoveMemberSchema = object({
+  userId: string(),
+});
+
+export const UpdateRoleSchema = object({
+  userId: string(),
+  role: picklist(["owner", "admin", "member"]),
+});