ifcviewer: preset-driven nav mouse bindings + a "Web" preset (desktop + web)

Make orbit/pan/select mouse bindings pure data owned by ViewportCore so both
hosts and every preset share one source of truth, and add a "Web" preset. This
rounds out the matrix: the desktop gains a web-style scheme and the web inherits
all presets, with no per-platform hardcoding.

- Core: NavBindings { orbit, pan, select button + modifier } + setNavPreset
  ("blender" default | "rhino" | "revit" | "web") + navBindings(). Select is
  preset-driven too (was hardcoded LMB) so "web" moves it to RMB. web = orbit
  LMB, pan MMB, select RMB (LMB drag orbits with no click/drag ambiguity; RMB
  click-selects / drag-marquees). NavMod uses "Plain" not "None" (X11 #defines
  None to 0L).
- Desktop ViewportWindow: applyNavPreset sources the core table (mapped to Qt);
  marquee-arm / single-pick dispatch keys off select_button_. Default stays
  blender → no behaviour change.
- Desktop config: AppSettings::NavPreset gains Web + navPresetName(); the
  Settings dialog lists it. This also FIXES a pre-existing gap — the preset combo
  was persisted but never applied (only WGPU_NAV_PRESET env worked). MainWindow
  now applies the persisted preset at startup (env override still wins) and live
  on navPresetChanged, so all four presets actually work from the dialog.
- Web main_web: classifyPress routes the pressed button through navBindings()
  (orbit/pan/select), defaulting to the "web" preset; context menu already
  suppressed so RMB is free.

Tests: setNavPreset table (Catch2, 123 total); web smoke select tests use RMB.
BonsaiViewer builds; 9/9 web smoke.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/ifcviewer-web/tests/smoke.spec.mjs

@@ -261,7 +261,7 @@ test('click selects an object and the highlight renders (async pick)', async ({
   const cx = box.x + box.width / 2;
   const cy = box.y + box.height / 2;
   const before = await shot(page);
-  await page.mouse.click(cx, cy);
+  await page.mouse.click(cx, cy, { button: 'right' });  // Web preset: RMB selects
   await page.waitForTimeout(600);  // async pick result + flush + render
   const after = await shot(page);
   expect(
@@ -330,8 +330,8 @@ test('hide selected removes geometry after a pick', async ({ page }) => {
 
   const box = await page.locator('#viewer-canvas').boundingBox();
   const before = await shot(page);
-  // select whatever is under the centre, then hide it
-  await page.mouse.click(box.x + box.width / 2, box.y + box.height / 2);
+  // select whatever is under the centre (Web preset: RMB selects), then hide it
+  await page.mouse.click(box.x + box.width / 2, box.y + box.height / 2, { button: 'right' });
   await page.waitForTimeout(400);
   await page.evaluate(() => window.Module._hide_selected_c());
   await page.waitForTimeout(400);