feat: add assert_str_matches! macro with wildcard support and colored diff

[wjones127]

Summary

• Replace assert_string_matches() with new assert_str_matches! macro
• Line-by-line ... wildcard matching (matches any content within a line)
• Colored diff output on failure (red for extra, green for missing, dim for wildcard captures)
• File/line/column info in panic messages

Test plan

• Added unit tests for the macro and internal matching functions
• Verified existing tests using the macro still pass

🤖 Generated with Claude Code

[github-actions]

Code Review - P0: Line alignment algorithm may produce confusing output for substitution cases. P1: assert_plan_node_equals signature changed from Result to unit type. P1: trim_whitespace appears unused after refactor.

[github-actions]

Full details on the issues above:

P0 - Line alignment (test.rs:553-588): The greedy lookahead in compare_strings can misalign substitutions. For actual=[A,X,B,C] vs expected=[A,Y,B,C], X and Y would be marked extra/missing in potentially confusing order. Add a test case to document expected behavior.

P1 - API change (test.rs:621-627): assert_plan_node_equals changed from returning lance_core::Result to (). This forces panics instead of allowing error propagation with ?. Check for external callers.

P1 - Dead code: trim_whitespace appears unused after refactor since compare_strings trims inline. Remove if unneeded.

Good: yansi is test-only, good test coverage for macro, correct cfg(test) guards.

[codecov]

Codecov Report

❌ Patch coverage is 86.72199% with 32 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
rust/lance/src/utils/test.rs	84.31%	29 Missing and 3 partials ⚠️

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