Zoom the Parametric EQ's dB with the wheel, saved on its node (#376)

Close moves of a few dB were hard to set and to see on a curve that
always spans -24 to +24 dB. The wheel on free space now zooms the dB
the curve shows, and the node's small curve shows the same range.

- The range is one of ±3, ±6, ±12, ±24 and ±48 dB, always the same
  either side of 0. Up zooms in.
- It is saved on the node as `range`, so it is back after loading.
  Like the game scale (#226) it is no undo step. EditorState gets
  `setNodeView` for such a setting of a node.
- The lines across the curve follow the range: every 1, 2, 3, 6 or
  12 dB. A handle whose gain lies beyond the range stays on the edge,
  in sight and in reach.
- The wheel over a handle still turns the band's Q. It no longer does
  so anywhere while a band is picked: after opening, a band nearly
  always is, and the zoom would be out of reach.
- `EqArea` carries the range, so the tab and the node map dB alike.
  The spectrum keeps its own scale.

Tests:
- Unit parametric-eq: 16 green, 5 new (range in compile and save,
  node picture, wheel steps, grid lines, handle on the edge)
- Counter-check: the node's picture without the saved range turns
  the new picture test red
- e2e 34 (melektaus-atx): ALL PASSED, 99 checks, 1 new
- Gate (melektaus-atx): CHECK EXIT 0, 275 files, 4252 tests

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

README.md

@@ -47,7 +47,7 @@ npm run build        # writes dist/ and regenerates index.html; the folder is wh
 The browser suite and the three example games need a machine with a GPU:
 
 ```bash
-node tools/seed-e2e.mjs && node tools/e2e.mjs      # the editor, 1921 checks (GM_STEPS=20 for one step)
+node tools/seed-e2e.mjs && node tools/e2e.mjs      # the editor, 1922 checks (GM_STEPS=20 for one step)
                                                    #   every tool signs in first – see the Accounts page
 node tools/seed-jumprun.mjs && node tools/smoke-jumprun.mjs
 node tools/seed-tetris.mjs && node tools/smoke-tetris.mjs