FE Architecture GBAC-01: Core Scaffolding & Initial Guard Implementation

### Description

The files should live under `src/router/` and `src/router/guards`

The goal of this task is to implement the core infrastructure for Guard-Based Access Control. This includes the centralized registry, the orchestrator within the router, and the initial set of guards required to support basic application security.

By the end of this task, the router should be capable of reading meta.guards and executing the associated logic before any component is mounted.

Tasks:
1. The Guard Contract
2. Initial Guard Implementation
- auth
- guest
- permissions
- role
- feature
3. The Singleton Registry
4. The Orchestrator

Abstractions for each can be found on the parent issue.

### Epic/Story

_No response_

### Have you provided an initial effort estimate for this issue?

I have provided an initial effort estimate

Read the abstractions on the parent issue first, then inspect the existing router under src/router/. Implement the guard contract, auth, guest, permissions, role, and feature guards under src/router/guards, plus the registry and router orchestrator. Done means the router reads meta.guards and executes the associated logic before any component is mounted.

Written by the indexing model from the issue text.