[Tracking] jsfeat parity, refactor and modernization roadmap

[kalwalt]

Roadmap

Tracking issue for the jsfeatNext <-> jsfeat parity, refactoring and modernization effort.
Full plan: docs/jsfeat-parity-and-refactor-audit.md

Work items

• Phase 0 gate - test harness: Test harness: Vitest characterization tests vs jsfeat (Phase 0 gate) #39
• Feature parity audit (Axis 1): Feature parity audit: function & parameter level vs jsfeat (Axis 1) #45
• API/behavioral parity (Axis 2): API/behavioral parity: static-vs-instance, double namespace, per-instance cache (Axis 2) #41
• De-duplicate stubs/monolith (Axis 3/4): Refactor: de-duplicate type-only stubs and the jsfeatNext.ts monolith (Axis 3/4) #47
• Target architecture (Axis 4): Refactor: target architecture (thin aggregator, one class per module, shared cache, static facade) #40
• Build modernization -> Vite (Axis 5): Build modernization: migrate webpack to Vite + dependency cleanup (Axis 5) #42
• Port haar (Appendix A): Port haar module (Haar cascade object/face detection) #43
• Port bbf (Appendix A): Port bbf module (BBF face detection) #44

[kalwalt]

Updating the checklist — 3 of 8 items shipped in 0.8.0:

• Phase 0 gate - test harness: Test harness: Vitest characterization tests vs jsfeat (Phase 0 gate) #39
• Feature parity audit (Axis 1): Feature parity audit: function & parameter level vs jsfeat (Axis 1) #45 (substantial progress, not exhaustive — see comment there)
• API/behavioral parity (Axis 2): API/behavioral parity: static-vs-instance, double namespace, per-instance cache (Axis 2) #41
• De-duplicate stubs/monolith (Axis 3/4): Refactor: de-duplicate type-only stubs and the jsfeatNext.ts monolith (Axis 3/4) #47
• Target architecture (Axis 4): Refactor: target architecture (thin aggregator, one class per module, shared cache, static facade) #40 (partial — see comment there)
• Build modernization -> Vite (Axis 5): Build modernization: migrate webpack to Vite + dependency cleanup (Axis 5) #42
• Port haar (Appendix A): Port haar module (Haar cascade object/face detection) #43
• Port bbf (Appendix A): Port bbf module (BBF face detection) #44