fix(project-tree): scroll horizontally when rows are wider than the pane (#495)

Project view rows were locked to the pane width, so deeply nested files and long names were clipped with no way to read the rest. Rows now size to their content and the view scrolls horizontally.

Rows are virtualised, so the scroll range keeps the widest row until the rows change. Otherwise scrolling past a wide row would remove the scrollbar and reset the horizontal position. Other trees opt out and keep clipping long labels.

Co-authored-by: a-rookie-of-C-language <[email protected]>

src/ui/Tree.module.css

@@ -53,6 +53,18 @@
   color: var(--fg-strong);
   white-space: nowrap;
 }
+/* At least the visible width so the selection covers it; wider rows overflow the sizer. */
+.wideRow {
+  width: max-content;
+  min-width: 100%;
+}
+.contentWidth {
+  position: absolute;
+  top: 0;
+  left: 0;
+  height: 1px;
+  pointer-events: none;
+}
 .row:hover {
   background: var(--bg-tree-hover, color-mix(in srgb, var(--fg-strong) 4%, transparent));
 }