AuthPlugin should be loaded in both server and MSW modes, and gracefully handle missing HTTP server (support universal auth endpoints simulation)

[hotlong]

Problem

Currently, ObjectStack runtime (in both server and MSW/mock modes) does NOT load AuthPlugin by default in the kernel or in the configuration of most app examples (e.g., objectstack-ai/objectui, etc).

• In server mode (HonoServerPlugin active), AuthPlugin works and registers /api/v1/auth/* endpoints and integrates better-auth backend.
• In MSW/mock mode (pnpm dev), the kernel does not load AuthPlugin at all, and HttpDispatcher.handleAuth() cannot simulate /api/v1/auth/* endpoints, leading to 404 errors for registration and sign-in flows.
• There is no fallback built into runtime for better-auth endpoints when AuthPlugin is not present.

Expected

• AuthPlugin is loaded in both server and MSW/browser test environments wherever user authentication is needed.
• In MSW mode, AuthPlugin should gracefully skip HTTP route registration if HonoServerPlugin/http-server is missing, BUT it should still register the 'auth' service so HttpDispatcher.handleAuth() can mock/simulate auth flows (sign-up, sign-in, etc.) using in-memory ObjectQL.
• Most app scaffolds (.config.ts and kernel factories) should include AuthPlugin by default (unless explicitly testing an unauthenticated app).
• As fallback for legacy cases, HttpDispatcher.handleAuth() should provide a mock implementation for core better-auth endpoints if AuthPlugin is missing (for high-fidelity MSW mock environments).

Solution

• Update AuthPlugin to make route registration optional/graceful when no HonoServer/http-server is available (allow mock/test environments to proceed without errors).
• Update kernal factories (e.g., in objectui, studio, etc) and config scaffolds to include AuthPlugin by DEFAULT.
• Document MSW/mock usage patterns with AuthPlugin, and clarify minimal required configuration for mock mode (secret, ObjectQL driver, etc).
• Optionally: extend HttpDispatcher.handleAuth() to provide safe mock fallback for registration/sign-in flows if 'auth' service is not present.

Impact

• Developers can run server OR pnpm dev (MSW mode) and still register/authenticate test users (sign-up, sign-in, sign-out, get-session, etc.).
• End users no longer encounter 404s for registration flows in Mock Console.

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Please see details in objectstack-ai/objectui issue for how the frontend expects MSW mode to behave.