fix(browser): guard Playwright pageError undefined-location crash (CC-161)

[voodoologic]

CC-161 — the disease behind CC-141 / CC-160 driver deaths

Playwright 1.60's vendored Node driver (coreBundle.js) reads pageError.location.url unconditionally. Firefox/Camoufox can emit a page error with no location (cross-origin "Script error.", CSP, some uncaught errors). LinkedIn triggers it deterministically; jobright.ai never does. The unguarded read throws a synchronous TypeError: Cannot read properties of undefined (reading 'url') in the Node event loop → the whole driver process exits → every subsequent call returns "Connection closed while reading from the driver" (the CC-141/160 "driver death"). CC-141/160 made the crash survivable but a relaunched LinkedIn scrape re-crashes on the same pageError, so LinkedIn never completes headed. This stops the crash.

Approach: A (surgical local patch) — verified, not assumed

Option B (Playwright bump) was verified infeasible: I installed and inspected the bundles — both 1.60.0 AND 1.61.0 still ship the unguarded read (the upstream guard, microsoft/playwright#41629, is unreleased). camoufox's own juggler-side fix (daijro/camoufox#625) is unreleased on PyPI (latest camoufox is 0.4.11, our pinned version, which lacks it). So a version bump does not fix the crash today, and Option A is the only fix that keeps Camoufox stealth.

• scripts/patch_playwright_pageerror.py — guards the two vendored crash sites (the PageError dispatcher + the _onPageError trace-event writer) with pageError.location?.url ?? null (+ line/column). Idempotent, shape-matched (fails loudly if upstream shape changes), repeatable after every uv sync / reinstall. Normal pageerror behaviour preserved when location is present (optional chaining short-circuits only on nullish).
• Dockerfile — runs the patch after the final uv sync so the built agents image carries the guard.
• tests/test_playwright_pageerror_patch.py — 6 tests: shape match, both crash sites, idempotency, loud-fail on unknown shape, and an assertion that the installed bundle carries the guard.

Local-dev wiring note

Local dev must run uv run python scripts/patch_playwright_pageerror.py after uv sync (and after python -m camoufox fetch reinstalls). The Dockerfile hook is in this repo (agents-owned). The parent's make/compose that drive local uv sync may want the same post-sync call — flagging for cc-orchestrator to decide if a parent-side Makefile hook is warranted (this PR does not touch parent).

Test results

• New: tests/test_playwright_pageerror_patch.py — 6 passed.
• Full agents suite: 503 passed.
• ruff: clean on all changed files. (Pre-existing tools/discover_sites.py syntax errors are unrelated and untouched.)

Build-don't-ship; no parent pin bump (Doug-gated). No graph structure change → no graph_static.json regen.

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