Return errors for recovered argument matching panics

[jakezwang]

Unordered argument matching recovers panics while trying expectations, but an error-valued panic currently leaves a nil error and incorrectly selects that expectation. Matching then panics again instead of trying a later valid expectation. Non-string panic values can also panic in the recovery handler.

Convert recovered values to errors in both implementations, preserving their text. Extend the existing recovery test and cover public Exec/Query calls that encounter a type-mismatched matcher before the matching expectation.

Validation: five regression cases fail before the fix. Required root race/coverage tests and go vet ./... pass; root race tests also pass with Go 1.18.10 and 1.27.1. The additional Go 1.27.1 all-package run times out in examples/orders, reproduced in the same test on the unchanged base. Whole-repository formatting also reports the same 16 pre-existing files on both versions; the changed files are formatted.