NickAkhmetov/Monorepo reorganization, eslint->biome, separate data loader packages, benchmarking

[NickAkhmetov]

This pull request introduces a monorepo structure for the Scellop project, adds a dedicated data loading package, and transitions the codebase to use Biome for linting and formatting instead of ESLint/Prettier. It also provides comprehensive developer documentation and updates project metadata and scripts to reflect the new structure and tooling.

Monorepo & Package Structure:

• Converted the project to a monorepo (scellop-monorepo) and moved data loading utilities into a new package @scellop/data-loading, with its own package.json, build scripts, and exports.
• Updated the root package.json to manage all packages, scripts, and dependencies at the monorepo level.
• scellop and the data loading logic live in the packages folder
• demo lives in the sites folder

Tooling & Linting Modernization:

• Replaced ESLint and Prettier with Biome for linting and formatting throughout the repo:
  • Added Biome config (biome.json) and removed all ESLint/Prettier configs and dependencies.
  • Updated VSCode settings and recommendations to use Biome as the default formatter for JS/TS/JSON files.

Developer Experience & Documentation:

• Added a detailed developer guide (.github/copilot-instructions.md) explaining project architecture, state management, data schema, export pipeline, development workflow, testing, code conventions, and integration points.
• Updated .vscode/settings.json for Biome integration and improved cSpell word list for project-specific terms.

Data Loading Package:

• Introduced a generic, extensible data loading API in @scellop/data-loading, including:
  • DataLoader and BaseDataLoader interfaces/classes for implementing new data sources.
  • Refactored and exported data wrangling utilities and type definitions for ease of future implementations with other data loading solutions (e.g. a more low-level zarr loader, or a local file loader for anndata)

Cleanup & Miscellaneous:

• Removed legacy or redundant files and scripts, such as the old ESLint config and the demo entrypoint.
• Minor formatting and config updates for consistency.

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Monorepo and Package Structure

• Converted project to a monorepo (scellop-monorepo), moving data loading utilities to a new package with its own build/test scripts and exports.
• Updated root package.json to manage scripts and dependencies for all packages.

Tooling Modernization

• Replaced ESLint/Prettier with Biome for linting and formatting; removed old configs and dependencies, added biome.json.
• Updated VSCode settings and recommendations to use Biome as the default formatter.

Developer Documentation

• Added comprehensive developer instructions covering architecture, patterns, workflow, and gotchas in .github/copilot-instructions.md.

Data Loading API

• Introduced a generic, extensible data loading API (DataLoader, BaseDataLoader) and refactored data wrangling utilities for modularity and reuse.

Cleanup

• Removed legacy ESLint config and demo entrypoint, and made minor config/formatting improvements.

TODOs:

• Migrate docs site created by @thomcsmits into this repository
• Confirm widget development still works as expected
• Confirm netlify deploy previews still work