fix(cli): honor explicit URL transport

[mikamikasuki]

Description

The client CLI does not reliably honor an explicit --transport for URL targets. For example, an SSE URL with a query string can be rewritten by appending /sse to the query value, while an explicitly selected HTTP transport can still be inferred as SSE from the URL path.

Honor the selected transport and preserve URL query parameters when applying transport-specific path handling.

Closes #5525

Contribution type

• Bug fix (simple, well-scoped fix for a clearly broken behavior)
• Documentation improvement
• Enhancement

Checklist

• This PR addresses an existing issue (or fixes a self-evident bug)
• I have read CONTRIBUTING.md
• I have added tests that cover my changes
• I have run uv run prek run --all-files and all checks pass
• I have self-reviewed my changes
• If I used an LLM, it followed the repo's contributing conventions (not generic output)

[github-actions]

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