v6: SortCore step-generator engine, 4 new algorithms, complexity profiler

[Sebby1770]

What this does

Rebuilds the Sort Lab's engine around a single testable core and adds an empirical complexity lab on top of it.

sorting-core.js — one implementation, three consumers

All sorting logic now lives in a dependency-free module of pure step generators (SortCore in the browser, CJS in Node — same pattern as pathfinding-core.js). Each algorithm yields a stream of ops (compare / swap / write / touch / counts / mark / narrate / gap / digitExp), and:

• the page's SortRunner animates the stream (metrics, sound, heatmap, narration, step mode all preserved — ~450 lines of duplicated per-algorithm animation code deleted),
• the tests run it headlessly,
• the profiler counts it.

Four new algorithms (10 → 14)

	Why it's interesting
Comb Sort	bubble sort with a ÷1.3 shrinking gap — kills turtles
Gnome Sort	the simplest stable sort — one loop, no nested indices
Cycle Sort	provably minimal writes (≤ n) — the writes metric finally gets a star
TimSort (simplified)	insertion-sorted minruns + merges with the already-ordered shortcut

All four are wired into the select, race mode, tournament, quiz, learning cards, and profiles.

📈 Complexity Profiler

One click benchmarks all 14 algorithms at n = 16…512 on the current dataset shape, draws a log-log chart, and least-squares-fits each line's slope — the measured exponent k in O(nᵏ) — next to the theoretical class. Verified in-browser: radix/counting measure n^1.00, merge/heap/tim land at n^1.2–1.3, bubble at ~n^2.

Tests — 47 new (66 total, still zero dependencies)

node --test tests/sorting.test.js covers: correctness for every algorithm on 8 dataset shapes + edge cases, input non-mutation, stability proofs for the 8 stable sorts (tagged-key trick), cycle sort's ≤ n write bound and 0-writes-on-sorted property, exact bubble counts on reversed input, and exponent-estimator checks that separate quadratic from linearithmic growth.

Also

• Service worker cache → v6, precaches sorting-core.js
• README (14-algorithm table, architecture note, profiler docs) + CHANGELOG v6 entry

Verification

• ✅ 66/66 node tests pass
• ✅ Live page: tournament runs all 14 through the new driver; profiler renders chart + table; no console errors

🤖 Generated with Claude Code