- compile groups routes ServeMux refuses side by side into overlap families
and registers each under one generated method-less pattern
- the family handler tries members in registration order on literals and
Where constraints, sets their path values and runs their own wrapped chain
- no match answers the bare 404; a method mismatch answers ServeMux's 405
and Allow for the same table without the overlap
- unsupported shapes (same shape, {name...}, shadowing route) fail at boot
- README and docs/services/routing.md describe the behaviour
