FE-1535: Sweep parameters as intervals with a range slider

[kube]

Important

Experimental
Behind the Parameter sweeps feature flag.

Summary

Before this PR, sweep parameters declared min, max, and a value count, five by default. Navigator computed one grid point at a time. Declaring the count was noise. Five points is too coarse to explore with.

Sweep now declares an interval only. Navigator selects a region of it with a range slider: whole interval by default, resizable, collapsible to a point. Region samples progressively. Drawer shows the merged distribution over it.

Links

• Ticket FE-1535
• Docs Parameter sweeps
• Docs Experiments

Changes

UI

• Navigator gets one RangeSlider per parameter

  RangeSlider is a new two-thumb @hashintel/ds-components component whose thumbs may coincide.
  Each slider carries a Range/Point control.
  Sweep navigator is its only user.
  Drags commit on release, so a gesture cancels at most one batch.

• Status line counts sampled cells and runs for regions
• Create drawer asks for min and max only

  200-combination cap and its warnings are gone.
  Sampling is lazy, nothing is enumerated up front.

• Surface view samples an 11-position sub-grid per axis

  Sub-grid lives in the same quantized space.
  Other parameters hold at the middle of their selected range.
  Clicking the surface collapses both shown axes to a point at the clicked position.

Core

• Range selection samples its region progressively

  enumerateRegionCells visits cells in a deterministic low-discrepancy order with Halton bases per axis.
  Session levels them rung by rung up the existing ladder.

• Drawer merges every cached cell in the region

  Distribution takes shape after a few points and sharpens with coverage.

• Point selection is a one-cell region and behaves as before
• Intervals quantize internally with SWEEP_AXIS_STEPS = 50

  Integer parameters step by whole numbers. Cells are cached by quantized position, so returning a slider to an earlier position restores its cached runs and distributions.

• Every batch still has one concrete value per parameter

  Per-batch scenario compilation, seeds, and GPU eligibility are untouched by range selections. Seeds stay common random numbers per rung.

Test coverage

• parameter-grid.test.ts, sweep-session.test.ts:

  Quantization, region enumeration, leveling, cache reuse, and the widened-region merge.

How to test

• Open Petrinaut preview on Vercel
• Viewport controls > Settings > Simulation > Parameter sweeps
• Load example > SIR
• Simulate > Experiments > Create
• Pick scenario, Sweep two numeric parameters, set min and max, Run
• Expect one slider per swept parameter with a Range/Point control in the results drawer
• Expect Range spanning its interval with two thumbs
• Click Surface
• Expect both parameters collapse to a point at the clicked position

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[TimDiekmann]

re-approval of pre-rebase

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