feat: make serve outbound display schema in and schema out

[tibisabau]

Summary

This PR enhances the xorq serve-unbound command to display the input and output schema of the expression being served. Closes #1211.

The code is generated by Claude Sonnet 4.5.

Changes

• Add exchanger instantiation
• Log schema-in
• Log schema-out
• Preserve existing server behavior

[Copilot]

Pull request overview

This PR enhances the xorq serve-unbound command to display the input and output schemas of the expression being served before starting the server. This helps users understand what data structure the server expects and produces.

• Add logging of schema-in (required input schema) and schema-out (output schema) information
• Instantiate UnboundExprExchanger to access schema metadata
• Preserve existing server behavior and functionality

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[codecov]

Codecov Report

❌ Patch coverage is 0% with 4 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
python/xorq/cli.py	0.00%	4 Missing ⚠️

Files with missing lines	Coverage Δ
python/xorq/cli.py	71.21% <0.00%> (-1.10%)	⬇️

... and 231 files with indirect coverage changes

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[codspeed-hq]

CodSpeed Performance Report

Merging #1454 will not alter performance

_{Comparing tibisabau:1211-serve-outbound-display-schemas (0a09afa) with main (a6f3e47)}

Summary

✅ 4 untouched