fix: respond with 500 when a handler throws a non-Error value

[RaphaelFakhri]

Fixes a request that never completes when a handler throws or rejects with a value that is not an Error.

Problem

run() only answers errors that pass isError(). If a handler throws a string, a plain object, or rejects with a non-Error value, the catch branch does nothing. No response is sent and the client waits until it times out.

module.exports = () => {
  throw 'boom';
};

Changes

• run() now always calls sendError(). A non-Error value is wrapped in an Error that includes the inspected value, so the client gets a 500 and the server logs the stack.
• Adds two tests: a synchronous throw of a string and a Promise.reject() with a plain object.

Testing

cd test && npx tap --ts suite/

Before the change, both new tests fail with a network timeout. After the change, all three suites pass.