debug(auth): log session cookie source

apps/web/src/lib/config.ts

@@ -7,12 +7,19 @@
  * Environment Variables:
  * - NEXT_PUBLIC_API_URL: The main API server URL (default: http://localhost:3001)
  * - NEXT_PUBLIC_ORCHESTRATOR_URL: The orchestrator service URL (default: same as API URL)
+ * - NEXT_PUBLIC_AUTH_MODE: Auth mode for web app (`real` or `mock`)
+ *   - If unset: development defaults to `mock`, production defaults to `real`
  */
 
 /**
  * Default API server URL for local development
  */
 const DEFAULT_API_URL = "http://localhost:3001";
+const DEFAULT_AUTH_MODE = process.env.NODE_ENV === "development" ? "mock" : "real";
+
+const VALID_AUTH_MODES = ["real", "mock"] as const;
+
+export type AuthMode = (typeof VALID_AUTH_MODES)[number];
 
 /**
  * Main API server URL
@@ -20,6 +27,34 @@ const DEFAULT_API_URL = "http://localhost:3001";
  */
 export const API_BASE_URL = process.env.NEXT_PUBLIC_API_URL ?? DEFAULT_API_URL;
 
+function resolveAuthMode(): AuthMode {
+  const rawMode = (process.env.NEXT_PUBLIC_AUTH_MODE ?? DEFAULT_AUTH_MODE).toLowerCase();
+
+  if (!VALID_AUTH_MODES.includes(rawMode as AuthMode)) {
+    throw new Error(
+      `Invalid NEXT_PUBLIC_AUTH_MODE "${rawMode}". Expected one of: ${VALID_AUTH_MODES.join(", ")}.`
+    );
+  }
+
+  if (rawMode === "mock" && process.env.NODE_ENV !== "development") {
+    throw new Error("NEXT_PUBLIC_AUTH_MODE=mock is only allowed when NODE_ENV=development.");
+  }
+
+  return rawMode as AuthMode;
+}
+
+/**
+ * Authentication mode for frontend runtime.
+ * - real: uses normal BetterAuth/Backend session flow
+ * - mock: local-only seeded mock user for FE development
+ */
+export const AUTH_MODE: AuthMode = resolveAuthMode();
+
+/**
+ * Whether local mock auth mode is enabled.
+ */
+export const IS_MOCK_AUTH_MODE = AUTH_MODE === "mock";
+
 /**
  * Orchestrator service URL
  * Used for agent management, task progress, and orchestration features
@@ -53,6 +88,8 @@ export const apiConfig = {
   baseUrl: API_BASE_URL,
   /** Orchestrator service URL */
   orchestratorUrl: ORCHESTRATOR_URL,
+  /** Authentication mode (`real` or `mock`) */
+  authMode: AUTH_MODE,
   /** Build full API URL for an endpoint */
   buildUrl: buildApiUrl,
   /** Build full orchestrator URL for an endpoint */