fix: improve Coloris color picker visibility and button clickability

- Fix grid layout: add second column for input (grid-template-columns: var(--input-h) 1fr)
- Ensure color picker button is clickable with cursor pointer and pointer-events auto
- Set color picker z-index to 10000 to display above all UI elements
- Add global styles to ensure Coloris button is always clickable

Fixes issues where:
- Color picker appeared behind ElementPopup
- Button was not consistently clickable
- Grid layout was missing second column definition

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

public/assets/css/style.css

@@ -304,13 +304,15 @@ input[type=number] {
 .field .input-with-color .clr-field {
   width: 100%;
   display: grid;
-  grid-template-columns: var(--input-h);
+  grid-template-columns: var(--input-h) 1fr;
   grid-gap: 1ch;
 }
 .field .input-with-color .clr-field button {
   grid-column: 1;
   position: relative;
   border-radius: var(--border-radius);
+  cursor: pointer;
+  pointer-events: auto;
 }
 .field .input-with-color .clr-field input {
   grid-column: 2;
@@ -351,17 +353,20 @@ input[type=number] {
   flex-shrink: 2;
 }
 
-.field-margin, .field-size {
+.field-margin,
+.field-size {
   display: inline-grid;
   width: calc(50% - 1ch);
   grid-template-columns: 6.5ch var(--input-w-small) 1fr;
   margin-bottom: var(--space-xs);
 }
-.field-margin input, .field-size input {
+.field-margin input,
+.field-size input {
   width: var(--input-w-small);
   padding-left: 0.75ch;
 }
-.field-margin:nth-of-type(odd), .field-size:nth-of-type(odd) {
+.field-margin:nth-of-type(odd),
+.field-size:nth-of-type(odd) {
   margin-right: 2ch;
 }