fix(e2e): harden browser launch on macOS + dismiss overlays mid-checkout (#163 #165)

[JonasJesus42]

Summary

• parity e2e hangs at browser launch (exit 144) on macOS with localhost #163 — parity e2e hung indefinitely at "Lançando browser" on macOS (exit 144 = watchdog SIGKILL after 3 min). Added --disable-setuid-sandbox and --no-zygote Chromium flags to prevent zygote/setuid sandbox deadlocks in macOS headless. Also wrapped chromium.launch() in a JS-level Promise.race with a 35 s backstop so the process always throws a catchable error even if Playwright's pipe-level 30 s timeout fails to fire.
• purchase-journey: detect and dismiss overlays that intercept clicks mid-flow (not just at step start) #165 — The go-checkout step (step 9) had no overlay handling. A newsletter popup triggered by exit-intent mid-flow (between minicart open and checkout click) would block the checkout button with no recovery. Added dismissOverlays (4 s cap) before the click loop and dismissBlockingOverlay (structural elementFromPoint check) on each failed navigation attempt before LLM recovery — mirrors the pattern already in steps 6 (add-to-cart) and 7 (open-minicart).

Test plan

• npx tsc --noEmit passes (verified)
• parity e2e --url http://localhost:<port> --flows purchase-journey launches browser within 30 s on macOS (no hang)
• Against a site with a newsletter popup mid-flow, step 9 logs overlay dismissal and reaches checkout

🤖 Generated with Claude Code

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Summary by cubic

Fixes a macOS headless Chromium launch hang, hardens checkout against popups, and bumps @decocms/parity to 0.17.6. Addresses #163 and #165.

• Bug Fixes
  • macOS: add --disable-setuid-sandbox and --no-zygote, keep --no-sandbox/--disable-gpu, and wrap chromium.launch() in a 35s Promise.race with a clearer timeout.
  • Step 9 checkout: pre-dismiss overlays (4s cap via dismissOverlays); if click is blocked, call dismissBlockingOverlay and retry once before LLM recovery.

^{Written for commit 7e2cfdc. Summary will update on new commits.}