set global error handlers and fallbacks

How to

• Register a problem solver with @problem_solver. You can match on specific exception types or status literals like 404.

Example

from lihil.problems import problem_solver
from lihil.vendors import Response

@problem_solver
def handle_404(req, exc: 404):
    return Response("resource not found", status_code=404)

Notes

• A solver for a specific exception takes precedence over a status-code solver.

References

• http/error-handling.md:1