feat(variation): author localized torque loci

[d-sorgcodexagent]

Summary

• add PyQt6 and React authoring controls for deterministic localized shoulder/wrist commanded-torque windows
• constrain locus selection to stable topological joint IDs, compatible swing/double-pendulum contexts, and effective RK4 half-open time bounds
• preserve exact plan IDs, groups, high-precision fields, and per-field loaded authority while rejecting coercive or invalid imports atomically
• retain the approved browser/security foundation from parent test(rate-web): add trusted production Worker browser gate #4413

Verification

• 190 focused Python/PyQt/core tests
• 780 React tests, TypeScript, ESLint, production build
• 5 real Chromium Playwright workflows after integration
• Ruff, MyPy, docs governance, diff and conflict gates
• all cumulative changed source/test files <=400 LOC; official 500 gate green
• independent exact-head GO review

Stack

Draft child of #4413. React authoring is available but localized dynamics/results/export still fail closed; Rust parity, complete raw state/event/torque persistence, broader localized sources, and full visual/accessibility certification remain open.