feat(ui): expose --bim-label--us, --bim-input--maxw, drop slider icon dup

* Label: user-select reads from a new --bim-label--us token (defaults
  to none, preserving prior behavior). Lets a host scope (e.g. a
  properties table) opt its label cells into selectable text.

* Input: the :host(:not([vertical])[label]) .input { max-width:
  fit-content; } rule now reads from --bim-input--maxw. Defaults
  unchanged; overriding to none lets a wrapping component (e.g. a
  full-width slider in a panel) stretch the input area instead of
  shrinking it to its current value's text width.

* NumberInput: in slider mode, the inner pref-label only renders
  when this.pref is set. Previously it also rendered when only icon
  was set, which duplicated the icon (the outer bim-input wrapper
  already shows it next to the label). Net effect: passing only
  icon now shows it once, in the label area.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: agviegas

packages/core/src/components/Input/index.ts

@@ -55,7 +55,7 @@ export class Input extends LitElement implements HasValue, HasName {
     }
 
     :host(:not([vertical])[label]) .input {
-      max-width: fit-content;
+      max-width: var(--bim-input--maxw, fit-content);
     }
   `;
 

packages/core/src/components/Label/index.ts

@@ -20,7 +20,7 @@ export class Label extends LitElement {
       display: block;
       white-space: nowrap;
       transition: all 0.15s;
-      user-select: none;
+      user-select: var(--bim-label--us, none);
       text-overflow: ellipsis;
       overflow: auto;
     }

packages/core/src/components/NumberInput/index.ts

@@ -445,10 +445,8 @@ export class NumberInput extends LitElement implements HasValue, HasName {
       </style>
       <div class="slider" @mousedown=${this.onSliderMouseDown}>
         <div class="slider-indicator"></div>
-        ${this.pref || this.icon
-          ? html`<bim-label
-              style="z-index: 1; margin-right: 0.125rem"
-              .icon=${this.icon}
+        ${this.pref
+          ? html`<bim-label style="z-index: 1; margin-right: 0.125rem"
               >${`${this.pref}: `}</bim-label
             >`
           : null}