Runtime component responsible for walking the routing tree and dispatching updates to the appropriate handler.

This module is called by the generated handle/2 function and should not be called directly in user code.

Dispatch algorithm

1. Iterate over top-level scopes in declaration order.
2. For each scope, evaluate all filters (AND logic, short-circuit on first false).
3. After each passing filter, call scope_extra/2 if implemented — the returned map is merged into context.extra before proceeding to remaining filters and child scopes. Sibling scopes receive the original, un-enriched context.
4. If all filters pass and the scope is a leaf (has a handler), call the handler with the enriched context.
5. If all filters pass and the scope is a branch (has children), recurse into children with the enriched context.
6. If no scope matches, return the context unchanged (no-op).