feat(data-structures/unstable): add includes() and removeAt() to Deque

[tomas-zijdemans]

• Add includes() method (matching Array.prototype.includes), and removeAt(index) for removing elements by index with negative-index support.
• Add a time-complexity table to the Deque class JSDoc to match BinaryHeap docs.
• Extract #maybeGrow() and #removeAtUnchecked() private helpers to reduce duplication

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 94.42%. Comparing base (224adef) to head (7994891).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #7083   +/-   ##
=======================================
  Coverage   94.42%   94.42%           
=======================================
  Files         630      630           
  Lines       50533    50546   +13     
  Branches     8964     8964           
=======================================
+ Hits        47717    47730   +13     
  Misses       2247     2247           
  Partials      569      569           

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[bartlomieju]

Thanks for the PR! includes() and removeAt() are good additions, and the refactoring (#maybeGrow, #removeAtUnchecked) is clean. The complexity table is a nice touch.

A few high-level points beyond the inline comments:

PR scope is broad

This bundles four concerns: new features (includes, removeAt), docs (complexity table), perf optimizations (iterator rewrite, toArray/#copyBuffer/from() changes), and refactoring (#maybeGrow, #removeAtUnchecked). I'd suggest splitting the perf optimizations into a separate PR — they have different risk profiles and the iterator behavior change in particular deserves focused review.

Codecov flags 4 uncovered lines

The coverage report shows 3 missing + 1 partial line in unstable_deque.ts. Worth checking which lines those are and adding test coverage.

[tomas-zijdemans]

Thanks. I've reverted the perf tweaks. Will consider a secondary PR for those.