feat(api): implement /users/me/preferences endpoint

Implements GET/PATCH/PUT /users/me/preferences. Fixes profile page 'Preferences unavailable' error by correcting the /api prefix in frontend calls and adding PATCH handler to controller.

Co-authored-by: Jason Woltje <jason@diversecanvas.com>
Co-committed-by: Jason Woltje <jason@diversecanvas.com>

apps/api/src/users/preferences.controller.spec.ts

@@ -0,0 +1,112 @@
+import { describe, it, expect, beforeEach, vi } from "vitest";
+import { UnauthorizedException } from "@nestjs/common";
+import { PreferencesController } from "./preferences.controller";
+import { PreferencesService } from "./preferences.service";
+import type { UpdatePreferencesDto, PreferencesResponseDto } from "./dto";
+import type { AuthenticatedRequest } from "../common/types/user.types";
+
+describe("PreferencesController", () => {
+  let controller: PreferencesController;
+  let service: PreferencesService;
+
+  const mockPreferencesService = {
+    getPreferences: vi.fn(),
+    updatePreferences: vi.fn(),
+  };
+
+  const mockUserId = "user-uuid-123";
+
+  const mockPreferencesResponse: PreferencesResponseDto = {
+    id: "pref-uuid-456",
+    userId: mockUserId,
+    theme: "system",
+    locale: "en",
+    timezone: null,
+    settings: {},
+    updatedAt: new Date("2026-01-01T00:00:00Z"),
+  };
+
+  function makeRequest(userId?: string): AuthenticatedRequest {
+    return {
+      user: userId ? { id: userId } : undefined,
+    } as unknown as AuthenticatedRequest;
+  }
+
+  beforeEach(() => {
+    service = mockPreferencesService as unknown as PreferencesService;
+    controller = new PreferencesController(service);
+    vi.clearAllMocks();
+  });
+
+  describe("GET /api/users/me/preferences", () => {
+    it("should return preferences for authenticated user", async () => {
+      mockPreferencesService.getPreferences.mockResolvedValue(mockPreferencesResponse);
+
+      const result = await controller.getPreferences(makeRequest(mockUserId));
+
+      expect(result).toEqual(mockPreferencesResponse);
+      expect(mockPreferencesService.getPreferences).toHaveBeenCalledWith(mockUserId);
+    });
+
+    it("should throw UnauthorizedException when user is not authenticated", async () => {
+      await expect(controller.getPreferences(makeRequest())).rejects.toThrow(UnauthorizedException);
+      expect(mockPreferencesService.getPreferences).not.toHaveBeenCalled();
+    });
+  });
+
+  describe("PUT /api/users/me/preferences", () => {
+    const updateDto: UpdatePreferencesDto = {
+      theme: "dark",
+      locale: "fr",
+      timezone: "Europe/Paris",
+    };
+
+    it("should update and return preferences for authenticated user", async () => {
+      const updatedResponse: PreferencesResponseDto = {
+        ...mockPreferencesResponse,
+        theme: "dark",
+        locale: "fr",
+        timezone: "Europe/Paris",
+      };
+      mockPreferencesService.updatePreferences.mockResolvedValue(updatedResponse);
+
+      const result = await controller.updatePreferences(updateDto, makeRequest(mockUserId));
+
+      expect(result).toEqual(updatedResponse);
+      expect(mockPreferencesService.updatePreferences).toHaveBeenCalledWith(mockUserId, updateDto);
+    });
+
+    it("should throw UnauthorizedException when user is not authenticated", async () => {
+      await expect(controller.updatePreferences(updateDto, makeRequest())).rejects.toThrow(
+        UnauthorizedException
+      );
+      expect(mockPreferencesService.updatePreferences).not.toHaveBeenCalled();
+    });
+  });
+
+  describe("PATCH /api/users/me/preferences", () => {
+    const patchDto: UpdatePreferencesDto = {
+      theme: "light",
+    };
+
+    it("should partially update and return preferences for authenticated user", async () => {
+      const patchedResponse: PreferencesResponseDto = {
+        ...mockPreferencesResponse,
+        theme: "light",
+      };
+      mockPreferencesService.updatePreferences.mockResolvedValue(patchedResponse);
+
+      const result = await controller.patchPreferences(patchDto, makeRequest(mockUserId));
+
+      expect(result).toEqual(patchedResponse);
+      expect(mockPreferencesService.updatePreferences).toHaveBeenCalledWith(mockUserId, patchDto);
+    });
+
+    it("should throw UnauthorizedException when user is not authenticated", async () => {
+      await expect(controller.patchPreferences(patchDto, makeRequest())).rejects.toThrow(
+        UnauthorizedException
+      );
+      expect(mockPreferencesService.updatePreferences).not.toHaveBeenCalled();
+    });
+  });
+});