Clean up vortex_ensure_eq!

[connortsui20]

Most vortex_ensure_eq! calls build a message that repeats the two values being compared. The macro now includes those values automatically, so callers can omit the message or use it for context.

The default error shows both expressions and their values. Operands are borrowed and evaluated once, and custom messages are only evaluated on failure. This also fixes qualified vortex_ensure! calls that previously required a macro import.

Validation: five focused integration tests, two doctests, scoped Clippy and rustdoc with warnings denied, release checks for the affected import changes, and formatting passed. CI Rust lint and docs are green.

[codspeed]

Merging this PR will not alter performance

⚠️ Unknown Walltime execution environment detected

Using the Walltime instrument on standard Hosted Runners will lead to inconsistent data.

For the most accurate results, we recommend using CodSpeed Macro Runners: bare-metal machines fine-tuned for performance measurement consistency.

✅ 2147 untouched benchmarks
⏩ 461 skipped benchmarks¹
🗄️ 1 archived benchmark run²

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_{Comparing ct/ensure-eq-hygiene (4681c2d) with develop (a88a2d6)}

Footnotes

1. 461 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

2. 1 benchmark was run, but is now archived. If it was deleted in another branch, consider rebasing to remove it from the report. Instead if it was added back, click here to restore it. ↩