feat: expose Measure in the Draw expansion

assets/icons/measure.svg

@@ -0,0 +1,3 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" role="img" aria-label="Measure" fill="none" stroke-linecap="round" stroke-linejoin="round">
+  <path d="M3 20L21 4M4 7h11M4 4v6M15 4v6" stroke="#B4B6B9" stroke-width="1.4"/><path d="M6 14l4 4M12 9l4 4" stroke="#6DB7ED" stroke-width="2"/>
+</svg>

src/ui/ribbon/draw_tools/07_measure.rs

@@ -0,0 +1,6 @@
+Tool {
+    command: "MEASURE",
+    label: "Measure",
+    icon: include_bytes!(concat!(env!("CARGO_MANIFEST_DIR"), "/assets/icons/measure.svg")),
+    options: &[],
+}