Initial open-source release

Claude-Session: https://claude.ai/code/session_01B65qLEKnkeYTGdbwhLpjCu

src/workbench/Workbench.module.css

@@ -0,0 +1,23 @@
+.workbench {
+  height: 100%;
+  display: flex;
+  flex-direction: column;
+  min-width: 0;
+  background: var(--bg-app);
+  color: var(--fg);
+}
+/* Islands frame; the project colour washes in from the top-left corner (IDEA project gradient). */
+.framed {
+  background:
+    radial-gradient(
+      600px 300px at 0 0,
+      color-mix(in srgb, var(--project-color) var(--project-gradient-strength, 22%), transparent),
+      transparent
+    ),
+    var(--bg-frame);
+}
+
+/* Settings › Appearance › "Use project colors in main toolbar" off. */
+:global(:root[data-project-colors="off"]) .framed {
+  background: var(--bg-frame);
+}