CODAP-1506: add per-category point shape controls - #2693

Add the shape dropdown to each legend category row, and to the single Points
row shown when no legend attribute is assigned. Gated behind a new pointShapes
feature flag owned by LEADS, so `features=LEADS` turns the whole set on.

Nothing renders a shape yet -- every point still draws as a circle until
CODAP-1504 lands the geometry. The control writes through to the model from
CODAP-1505, so the UI is exercisable now and the shapes appear when the
renderer learns to draw them.

The trigger is icon only: with an icon and a text label the category name is
squeezed to about 55px and a value like "water" truncates. The open menu carries
icon plus label, and marks the current shape in bold. Both take their fill from
the category's own color, so a row's two controls describe the same category.

Assets
------

Seven SVGs exported from the design prototype, adapted to the repo's icon
convention: fill is currentColor so a row can tint them, and the decorative
title/role attributes are dropped so the control supplies the accessible name.

They use the .nosvgo.svg extension, which keeps SVGR (still React components,
as the tinting requires) while skipping svgo. That matters because svgo's
removeViewBox drops the viewBox once width and height are present, and those
attributes are what give the glyph intrinsic dimensions. Without them the svg
contributes nothing to its parent's intrinsic width, and the trigger sizes
itself to padding plus arrow alone.

Layout
------

Trigger geometry mirrors .color-picker-thumb beside it -- same padding, same
gap, same 24px inner element -- so the two controls in a row are the same size
by construction rather than by coincidence. Popover values follow the
prototype's own .pt-popover and .pt-listbox.

Each glyph is pinned inside a plain box with inset: 0 rather than placed by
flex layout. Laid out normally, the svg rendered outside its parent's box --
measured 3px above and left of it in the trigger, and stacked at a single point
in the menu. The cause was not identified; taking the glyph out of the flex
layout path removes the failure rather than explaining it.

Note that a plain className on a react-aria component REPLACES its default
class, so the trigger carries point-shape-thumb and not react-aria-Button. The
stylesheet says so, because adding .react-aria-Button to those selectors would
silently match nothing.

Row alignment
-------------

The category row distributes with space-between, so a control following the
label tracked the label's width and the controls staggered from row to row. The
label now absorbs the free space and truncates, which pins both controls to the
right edge and gives the category name the width the panel was widened for.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Ctmv18kjkPWnUq5bek5nrH

The map mounts these controls for its polygon layers as well as its point
layers, and a polygon layer marks itself with a negative point size -- the same
sentinel that already hides the Point Size slider. The shape gates ignored it,
so a polygon layer's fill row was relabeled "Points" and offered a shape that
cannot reach polygon rendering.

Decided once where the display description is in hand and passed down, since the
per-category gate is in a child component that does not receive it.

The test's mock description had no point size at all, which the real model
always has, so completing the mock was part of the fix rather than a
consequence of it.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Ctmv18kjkPWnUq5bek5nrH

…l shape in inspector with color gradient representing numeric legend range.

Only the trigger took the gradient, so the menu's options kept the display's own
point color. That color stops describing anything once a numeric legend governs
the plot: a shape chosen purple before the legend was applied left seven purple
options in a plot with no purple points in it.

Each option previews the points that choosing it would produce, which is what
the menu already does elsewhere -- the display's color with no legend, the
category's color in a categorical row. With a numeric legend that preview is the
range, the same one the trigger shows.

The trigger and the options now share one style, so the two cannot drift.

The rule routing a glyph's fill through the custom property moves out of the
trigger's block to cover both. The menu is rendered in a portal, outside the
palette the trigger is scoped to, so a rule nested there could not reach it and
the property would have had no effect on an option.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Name the polygon sentinel. A negative point size is how a polygon layer says it
has no point, and two places compared against it directly with a comment saying
what the comparison meant. `isPolygon` says it instead, and the shape gate and
the Point Size slider now ask the same question -- which is the thing they were
not doing when one of them offered a shape a polygon could not take.

Keep the palette thumbs in sync in code rather than in a comment. The color
picker's and the shape control's triggers repeated a dozen declarations with a
comment on one saying it mirrored the other; both include a mixin now. Same for
the glyph box and the glyph inside it, which the trigger and the menu items each
declared separately.

That left a comment describing padding the rule does not have -- it claimed less
padding on the left, over a uniform 3px -- which is the kind of drift the mixin
exists to prevent.

Answer in code why one thumb needs `!important` and the other does not: the
color picker's trigger is a react-aria Button and inherits rules that set its
height and padding, while the shape control passes a plain className, which
replaces that class.

Define `hasFillGradient` once rather than testing the same condition twice.

Drop the references to "the prototype", which named something a reader of this
file cannot reach, and the comments that described the markup beneath them.

Rewrite the note on the hidden SelectValue, whose first sentence buried what the
element is for.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>