feat(bytesbuf): add BytesView::to_vec()

[sandersaares]

Adds BytesView::to_vec(), which copies the view's full byte sequence into a new Vec.

The method iterates over all spans in logical order via slices(), pre-allocates exact capacity from len(), and leaves the view itself unchanged.

Includes a doctest plus unit tests covering single-span, multi-span, and empty views.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.9%. Comparing base (fc13464) to head (ba44ae3).

Additional details and impacted files

@@          Coverage Diff          @@
##            main    #495   +/-   ##
=====================================
  Coverage   99.9%   99.9%           
=====================================
  Files        336     336           
  Lines      24829   24836    +7     
=====================================
+ Hits       24818   24825    +7     
  Misses        11      11           

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[Copilot]

Pull request overview

Adds a convenience API to materialize a BytesView into an owned Vec<u8> by copying all spans in logical order, leaving the view unchanged.

Changes:

• Add BytesView::to_vec() implemented via len() + slices() with exact pre-allocation.
• Add rustdoc example for to_vec().
• Add unit tests for empty, single-span, and multi-span views.

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