bring tooling into 2026-era + visual improvements

[mathematicalmichael]

• upgrade as many deps as possible safely (leaving just jquery behind latest out of an abundance of caution)
• drop sass/scss. just using css now.
• modernize tooling
• adds tests
• dark mode: auto (default) | true | false
• pyproject.toml + uv + bun + vite
• datatables upgrade + restyling
• BIG FIX: categorical distributions are now equal-width bars and properly reflect distributions (black lines vs purple bars)

[mathematicalmichael]

another round of fixes, courtesy of codex:

Commit a50ebc8 - fix release-gate regressions and typing issues

• Fixed TypeScript release-check failures in prepublish-ts by setting tsc --module es2020 in package.json.
• Fixed Dropzone accept typing in src/dataproviders/upload.tsx.
• Updated React test harness root usage in src/hiplot_test.tsx to use createRoot.
• Added missing children typing in src/lib/resizable.tsx.
• Fixed invalid setState updater return in drag path ({} -> null) in src/parallel/parallel.tsx.

Commit 442e7ca - restore hiplot.render compatibility and dark mode defaults

• Restored window.hiplot.render(...) compatibility semantics in src/hiplot_web.tsx:
  • maintains a root per element
  • returns a HiPlot instance-compatible object when available (fallback to root)
• Restored default dark mode behavior to "auto" in build_props (src/hiplot_web.tsx).
• Added Playwright regression tests in tests/hiplot.spec.ts:
  • default auto dark mode when no query parameter
  • window.hiplot.render return object exposes getPlugin

Commit d2c4f49 - fix documentation warnings and include distribution plot guide

• Fixed docs title formatting in docs/contributing.rst.
• Added docs build instructions using uv in docs/contributing.rst.
• Added distribution_plot page to docs toctree in docs/index.rst.
• Added docs/_static/.gitkeep to satisfy Sphinx static path.
• Included docs/distribution_plot.md in published docs.

Commit c32a391 - fix distribution bin ordering to prevent mismatched rendering

• Fixed horizontal categorical distribution rendering order bug in src/distribution/plot.tsx.
  • Before: geometry could use reordered bins while density/length still came from original-index bins.
  • After: both geometry and density are computed from the same reordered list (binsInDisplayOrder), preventing visual mismatch.
• Initialized distribution state with current selected rows in src/distribution/plugin.tsx:
  • histData.selected now starts from props.rows_selected (instead of empty) to avoid first-render mismatch/flicker.

Commit 2ddb01b - improve docs reliability layout and fork messaging

• Added explicit community-maintained fork messaging in docs homepage (docs/index.rst), referencing archived upstream.
• Made docs demo iframes responsive (removed fixed-width and negative-margin styles) in:
  • docs/index.rst
  • docs/experiment_settings.rst
• Fixed broken/fragile docs links and wording:
  • Streamlit docs link updates (docs/getting_started.rst, docs/tuto_streamlit.rst)
  • issue tracker link and package naming in JS tutorial (docs/tuto_javascript.rst)
  • colormap doc link anchor in hiplot/experiment.py
• Added linkcheck_ignore for npm URL anti-bot false positives in docs/conf.py.
• Removed final docs warning by switching problematic literalinclude highlighting to plain text in docs/tuto_javascript.rst.

Commit 08a9add - fix categorical distribution mapping and seed demo data

• Fixed categorical horizontal distribution rendering alignment in src/distribution/plot.tsx.
  • Corrected mapping between category display slot and bin density source so bars/lines stay aligned with category labels after brush/keep filtering.
• Made demo fetches deterministic in hiplot/fetchers.py.
  • load_demo() now seeds RNG per demo URI and restores previous RNG state afterward.
• Added deterministic distribution demo in hiplot/fetchers_demo.py:
  • demo_distribution_colors_deterministic with fixed category counts.
• Added determinism unit test in hiplot/test_fetchers.py:
  • repeated load_demo("demo") returns identical color counts.
• Added Playwright regression in tests/hiplot.spec.ts:
  • brushing/filtering to keep only green on categorical c axis keeps distribution bars aligned and associated with green.

Validation runs

The following checks were run and passed after fixes:

• bun run prepublish-ts
• bun run build
• uv run pytest (25 passed)
• uv run --extra docs sphinx-build -b html docs docs/_build/html (no warnings)
• uv run --extra docs sphinx-build -b linkcheck docs docs/_build/linkcheck (passed)
• uv run pytest (26 passed, after adding deterministic demo test)
• bunx playwright test (20 passed, after adding categorical distribution regression test)