fix: return 404 instead of 301 for trailing slash (issue #245)

[devfeel]

Description

Fix issue #245: URL with trailing slash /hello/xx/ should return 404 instead of 301 redirect when matching route /hello/:name

Changes

• Set RedirectTrailingSlash to false in router initialization
• Now returns 404 like net/http does

Testing

Verified with curl:

• Before: curl /hello/xx/ → 301 Moved Permanently
• After: curl /hello/xx/ → 404 Not Found

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commit