Let graphs zoom out to an eighth (#387)

With the Chip and the Filter drawn as devices, a preset such as the
Laser is about 3060 units wide. In a window of 1280 px a fit then hit
the floor of 0.25 and cut the Notes node off on the left.

- ZOOM_LIMITS.min goes from 0.25 to 0.125. The graph zooms without
  steps, so one more step is the floor halved. 0.125 is also the
  smallest step of the scene view.
- It holds for the wheel, for Fit and for the node board of plugins.
- The grid still hides itself below 8 px, so it does not flicker.

Tests:
- Unit plugins and graph-framing: 55 tests green, the floor test now
  expects 0.125.
- e2e 06 (atx): ALL PASSED, 149 checks. Only a comment that named 0.25
  changed there.
- Gate (atx): CHECK EXIT 0, 285 files, 4377 tests.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/editor/graph/graphView.ts

@@ -12,7 +12,7 @@ import { ViewTween } from '../viewTween';
 
 /** Spacing of the background grid – and, with snapping on, of the positions a drag can leave. */
 export const GRID_STEP = 24;
-export const ZOOM_LIMITS = { min: 0.25, max: 2.5 };
+export const ZOOM_LIMITS = { min: 0.125, max: 2.5 };
 /** Breathing room around the framed nodes, so they do not touch the edge. */
 export const FIT_MARGIN = 24;
 /** Below this on-screen spacing the grid is noise rather than orientation, so it is dropped. */