fix(#338): Standardize API base URL and auth mechanism across components

- Create centralized config module (apps/web/src/lib/config.ts) exporting:
  - API_BASE_URL: Main API server URL from NEXT_PUBLIC_API_URL
  - ORCHESTRATOR_URL: Orchestrator service URL from NEXT_PUBLIC_ORCHESTRATOR_URL
  - Helper functions for building full URLs
- Update client.ts to import from central config
- Update LoginButton.tsx to use API_BASE_URL from config
- Update useWebSocket.ts to use API_BASE_URL from config
- Update AgentStatusWidget.tsx to use ORCHESTRATOR_URL from config
- Update TaskProgressWidget.tsx to use ORCHESTRATOR_URL from config
- Update useGraphData.ts to use API_BASE_URL from config
  - Fixed wrong default port (was 8000, now uses correct 3001)
- Add comprehensive tests for config module
- Update useWebSocket tests to properly mock config module

Refs #338

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/web/src/lib/config.test.ts

@@ -0,0 +1,91 @@
+/**
+ * Tests for centralized API configuration
+ */
+
+import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
+
+// Store original env
+const originalEnv = { ...process.env };
+
+describe("API Configuration", () => {
+  beforeEach(() => {
+    // Reset modules to pick up new env values
+    vi.resetModules();
+  });
+
+  afterEach(() => {
+    // Restore original env
+    process.env = originalEnv;
+  });
+
+  describe("default values", () => {
+    it("should use default API URL when NEXT_PUBLIC_API_URL is not set", async () => {
+      delete process.env.NEXT_PUBLIC_API_URL;
+      delete process.env.NEXT_PUBLIC_ORCHESTRATOR_URL;
+
+      const { API_BASE_URL, ORCHESTRATOR_URL } = await import("./config");
+
+      expect(API_BASE_URL).toBe("http://localhost:3001");
+      expect(ORCHESTRATOR_URL).toBe("http://localhost:3001");
+    });
+  });
+
+  describe("custom values", () => {
+    it("should use NEXT_PUBLIC_API_URL when set", async () => {
+      process.env.NEXT_PUBLIC_API_URL = "https://api.example.com";
+      delete process.env.NEXT_PUBLIC_ORCHESTRATOR_URL;
+
+      const { API_BASE_URL, ORCHESTRATOR_URL } = await import("./config");
+
+      expect(API_BASE_URL).toBe("https://api.example.com");
+      // ORCHESTRATOR_URL should fall back to API_BASE_URL
+      expect(ORCHESTRATOR_URL).toBe("https://api.example.com");
+    });
+
+    it("should use separate NEXT_PUBLIC_ORCHESTRATOR_URL when set", async () => {
+      process.env.NEXT_PUBLIC_API_URL = "https://api.example.com";
+      process.env.NEXT_PUBLIC_ORCHESTRATOR_URL = "https://orchestrator.example.com";
+
+      const { API_BASE_URL, ORCHESTRATOR_URL } = await import("./config");
+
+      expect(API_BASE_URL).toBe("https://api.example.com");
+      expect(ORCHESTRATOR_URL).toBe("https://orchestrator.example.com");
+    });
+  });
+
+  describe("helper functions", () => {
+    it("should build API URLs correctly", async () => {
+      process.env.NEXT_PUBLIC_API_URL = "https://api.example.com";
+      delete process.env.NEXT_PUBLIC_ORCHESTRATOR_URL;
+
+      const { buildApiUrl } = await import("./config");
+
+      expect(buildApiUrl("/api/v1/tasks")).toBe("https://api.example.com/api/v1/tasks");
+      expect(buildApiUrl("/auth/signin")).toBe("https://api.example.com/auth/signin");
+    });
+
+    it("should build orchestrator URLs correctly", async () => {
+      process.env.NEXT_PUBLIC_API_URL = "https://api.example.com";
+      process.env.NEXT_PUBLIC_ORCHESTRATOR_URL = "https://orch.example.com";
+
+      const { buildOrchestratorUrl } = await import("./config");
+
+      expect(buildOrchestratorUrl("/agents")).toBe("https://orch.example.com/agents");
+      expect(buildOrchestratorUrl("/tasks/status")).toBe("https://orch.example.com/tasks/status");
+    });
+  });
+
+  describe("apiConfig object", () => {
+    it("should expose all configuration through apiConfig", async () => {
+      process.env.NEXT_PUBLIC_API_URL = "https://api.example.com";
+      process.env.NEXT_PUBLIC_ORCHESTRATOR_URL = "https://orch.example.com";
+
+      const { apiConfig } = await import("./config");
+
+      expect(apiConfig.baseUrl).toBe("https://api.example.com");
+      expect(apiConfig.orchestratorUrl).toBe("https://orch.example.com");
+      expect(apiConfig.buildUrl("/test")).toBe("https://api.example.com/test");
+      expect(apiConfig.buildOrchestratorUrl("/test")).toBe("https://orch.example.com/test");
+    });
+  });
+});