feat: add RouteOption::NAMESPACE for dynamic service resolution

[usernane]

Step 2 of 5: ServiceRouter integration (ADR-0006)

Problem

Some architectures (plugin systems, rapid prototyping) need services to be discoverable at runtime without restarting or clearing cache.

Proposed Change

Add RouteOption::NAMESPACE that enables dynamic resolution:

Router::api([
    RouteOption::PATH => '/apis/{controller}',
    RouteOption::NAMESPACE => 'App\\Apis',
    RouteOption::MIDDLEWARE => [...]
]);

When a request hits /apis/orders, the framework:

1. Extracts {controller} = orders
2. Scans App\Apis for a class with #[RestController('orders')]
3. Instantiates it and delegates to RequestProcessor

Acceptance Criteria

• RouteOption::NAMESPACE accepted by Router
• Dynamic resolution of controller name → class at request time
• Returns 404 if no matching #[RestController] found
• Works alongside existing route types

Backward Compatibility

New route option — no breaking changes.

[usernane]

Depends on: WebFiori/http#121 (RequestProcessor must exist first)
ADR: ADR-0006