refactor(web): extract JS results payload into payload module

[onuralpszr]

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

🧹 This PR refactors the web inference package by moving JS result serialization into its own module and improving reuse of default settings and fetch error handling in the TypeScript API.

📊 Key Changes

• ♻️ Extracted all JS-facing result payload logic from crates/web/src/lib.rs into a new dedicated file, crates/web/src/payload.rs.
• 📦 Moved serialization structs and conversion helpers like JsResults::from_results() into the new module, without changing the core result format.
• 🎨 Kept mask overlay and semantic segmentation payload generation intact, but relocated that logic to the new payload module for cleaner organization.
• 🧭 Updated imports in lib.rs to use the new payload::JsResults module and removed now-unneeded direct result imports.
• 🛠️ Added shared TypeScript constants for default thresholds:
  • confidence
  • IoU
  • keypoint visibility threshold
• 🌐 Added a reusable fetchOk() helper in web/src/index.ts to standardize network requests and error messages for models and images.
• ✏️ Cleaned up some documentation comments to better reflect that browser results are aligned with the native path.

🎯 Purpose & Impact

• ✅ Improves maintainability by separating payload-building code from the main WebAssembly binding logic, making the Rust web crate easier to read and extend.
• 🚀 Reduces duplication in the TypeScript frontend by centralizing default threshold values and fetch error handling.
• 🐞 Makes network failures easier to understand with clearer, more consistent error messages when loading models or images.
• 🔒 Low risk for users: this looks mainly like a refactor and cleanup, with behavior preserved rather than redesigned.
• 🧑‍💻 Helps future development by making it simpler to evolve browser-side inference results and web APIs without cluttering the main library file.

[UltralyticsAssistant]

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[UltralyticsAssistant]

🔍 PR Review

_{Made with ❤️ by Ultralytics Actions}

Clean refactor. The payload extraction appears behavior-preserving: imports were updated consistently, JsResults visibility is scoped appropriately with pub(crate), and the moved serialization/mask helper logic is unchanged in substance. I did not find any genuine bugs or regressions in the diff.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!

[UltralyticsAssistant]

🎉 Merged — thank you, @onuralpszr!

This is a thoughtful cleanup that makes the web inference stack easier to maintain and extend, from separating JS payload serialization into a dedicated module to centralizing TypeScript defaults and fetch error handling. As Leonardo da Vinci said, “Simplicity is the ultimate sophistication.” That fits this PR well: cleaner structure, less duplication, and clearer browser-side behavior without changing the user-facing results.

Really appreciate the care put into keeping behavior intact while improving the foundation for future work.