tests: un-skip sweep — 26 tests revived on the JSPI build, failures re-gated with fresh evidence

Empirical pass over every skip/fixme whose premise the JSPI migration
could have changed. Revived (verified green):

- Firefox wasm-budget guards RETIRED (drift-trio, drift-trio-fuzz,
  drift-trio-scenarios, ysync-two-tab, ysync-libsymbols): the JSPI
  build (~half the asyncify size) fits three editor tabs inside
  Firefox 153's per-process budget — +20 firefox collab tests.
- roundtrip 'pcbnew preserves items through a yjs round trip': the
  asyncify-fragile envelope parse it waited on is gone — both engines.
- drift-trio-scenarios S4/S4b: converge now (was KNOWN ~5-8%).
- pcbnew-collab + eeschema-collab 'a local move propagates A→B'.
- web eeschema-fp-selector, read-only-editor's fixme'd writer-stream
  test, footprint-browse-remote read path (chromium; firefox gated:
  FootprintEnumerate rows never appear in 60s — slow wasm tier
  suspected).

Still broken, re-gated with re-verified reasons:

- 3d-viewer raytracer engine toggle: still inert, both engines.
- maximize display geometry: wxDisplay reports 0x0 in the harness.
- web editor WRITE bridge (symbol/footprint × remote/spike): wedges at
  the New Symbol/Footprint dialog step on both engines — the
  web-e2e-rot 01 gap stands for writes.

Verify runs: kicad+wx touched files 93 passed / 0 failed / 7 skipped
(intended gates); web touched files 7 passed / 0 failed / 9 skipped.
lint:determinism + lint:ci-coverage green.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016X9eh1s5sTx1o9Em9KBuwR

tests/kicad/drift-trio.spec.ts

@@ -51,10 +51,10 @@ test.beforeAll(() => {
 /** Heavy editors exceed Firefox's per-content-process wasm budget at 2+
  *  instances (see ysync-two-tab.spec.ts) — at 3 it is strictly worse. */
 function skipFirefox(): void {
-  test.skip(
-    test.info().project.name.includes("firefox"),
-    "three heavy wasm tabs exceed Firefox's per-process wasm budget",
-  );
+  // 2026-08-13: guard retired — the JSPI build (~half the asyncify size) fits
+  // three editor tabs inside Firefox 153's per-process wasm budget; the
+  // whole file passes on kicad-firefox. Kept as a hook in case the wall
+  // returns with future growth.
 }
 
 // ── pl_editor: green baseline validating the trio plumbing itself ────────────