fix(ci): route occ-export-models.spec to chromium-ci (BIG_MODULE_SPECS)

720cff5 added occ-export-models.spec.ts (boots the ~190MB merged pcbnew
module, prefetches 17 model bodies, runs a 13MB OCC STEP export in the
occ_service worker — twice, serial) but never listed it in BIG_MODULE_SPECS,
so on CI it ran on the firefox project: headed under Xvfb with the
baseline-only WASM JIT and llvmpipe. That CPU storm ran concurrently with
the chromium-ci pool and starved the SwiftShader 3D-viewer opens past their
180s cap — 3d-viewer.spec:299 (edge-resize) timed out at openThreeDViewer in
runs 29076702564 (main) and 29090433643 (PR), and 29076702564 also dropped
occ-export.spec:105's menu click. In both red runs the last console line
before the 180s silence is the misrouted spec's export.

Add it to BIG_MODULE_SPECS like every other pcbnew.html-booting spec: it now
runs on chromium-ci (V8, headless SwiftShader) and firefox ignores it
(verified with CI=1 playwright --list).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VYxyBRJnKKExFcA5CRPXjM

tests/playwright-kicad.config.ts

@@ -116,6 +116,12 @@ const BIG_MODULE_SPECS = [
   // only boots the (small) occ_service module but shares the harness page.
   "**/occ-export.spec.ts",
   "**/occ-probe.spec.ts",
+  // occ-export-models boots pcbnew.html (merged module) + runs the model-shipping
+  // export — same V8 routing. Left off this list it ran on the CI firefox project
+  // (headed Xvfb, baseline-only WASM JIT): two serial heavyweight boots whose CPU
+  // storm starved the chromium-ci 3D-viewer opens past their 180s cap (runs
+  // 29076702564 / 29090433643 — 3d-viewer.spec:299 edge-resize red).
+  "**/occ-export-models.spec.ts",
   // ysync v2-wire repros/coverage: the two-tab file boots pcbnew + eeschema
   // (pl_editor cases ride along — only the browser changes), the repro files
   // boot pcbnew-collab.html / eeschema.html — same V8 routing.