feat: strip router path patterns from the OpenAPI document

[stareezy-1]

Summary

Fixes #922

Problem

Chi supports regex in path parameters, e.g. /users/{id:[0-9]+}, and huma routes them fine — but the same path is used verbatim as the OpenAPI paths key, so the generated document contains an invalid path:

"/users/{id:[0-9]+}": { ... }

Reproduction: register any operation on a regex path with humachi and inspect api.OpenAPI().Paths.

Fix

Normalize the documented path in AddOperation — {id:[0-9]+} becomes {id} — while leaving op.Path untouched so the router keeps the regex. The normalization uses a brace-aware scan, so quantifiers like {3} inside the pattern do not terminate the segment early ({id:[a-z]{3}} → {id}).

Tests

TestRegexPathParamNormalizedInOpenAPI in huma_test.go:

Assertion	Verifies
Paths contains /users/{id}	regex stripped from the document
Paths does not contain /users/{id:[0-9]+}	raw pattern not documented
GET /users/123 via the chi router	routing still works end to end

All existing tests continue to pass (go test -race ./...).