ui: assorted polish - Vue async fix, OrbitControls passive listeners, path-viewer + motor-view + indicators

- main.js: disable Vue async batching so reactive writes from
  hashchange listeners propagate synchronously (matches Vue 1's older
  default; avoids dropped DRO updates).
- orbit.js: pass {passive:false} to wheel/touch listeners so
  OrbitControls.preventDefault() actually suppresses page panning.
- path-viewer: opaque dark canvas (no flash from page background),
  zero-size guard, ResizeObserver cleanup on destroy.
- motor-view: stop clobbering user edits with controller state.
- estop/indicators/tool-view/path-viewer pug: rename FA4 icons to FA6,
  add viewBox to estop SVG, fix tool-view trailing newline.

src/pug/templates/tool-view.pug

@@ -433,4 +433,4 @@ script#tool-view-template(type="text/x-template")
           | Other settings according to the
           |
           a(href="https://buildbotics.com/upload/vfd/stepperonline-v70.pdf",
-            target="_blank") Stepper Online V70 VFD manual
+            target="_blank") Stepper Online V70 VFD manual