test(puppeteer): cover SharedWorker cursor restoration

[marcus-pousette]

Summary

• reuse the two existing cursor-restoration reload tests for SharedWorker + OPFS integration coverage
• let the persistent TreeCRDT fixture select a runtime without changing the default direct + OPFS suite
• rerun only that existing test group in Puppeteer's pinned Chrome
• keep the established Browserless visual suite unchanged
• install the pinned browser explicitly so the upstream node_modules cache cannot restore dependencies without a browser binary

Why

em should cover the user-visible “open, persist, reload, restore cursor” path. TreeCRDT owns the lower-level failed-open and stale-worker regressions, now covered by cybersemics/treecrdt#208. The exact over-64-byte pathname regression remains covered by cybersemics/treecrdt#221.

The legacy Browserless image hangs after persisted SharedWorker reloads with the current Puppeteer client. Puppeteer's pinned Chrome completes the same reload normally. Running only the two restoration tests there avoids an unrelated visual-snapshot migration.

Verification

• rebased onto the fork's current main after Bump @treecrdt/wa-sqlite to 0.3.2 #91 and Sync upstream main (2026-07-14) #93 merged
• focused SharedWorker + OPFS run: 2/2 passed locally and in GitHub CI
• unchanged full Browserless suite: 161 passed, 12 skipped
• TypeScript check
• focused Prettier check
• shell syntax check
• git diff --check

The workflow still runs the complete Browserless Puppeteer suite after the focused pinned-Chrome run. Puppeteer CI run