test(e2e): Playwright smoke test loading the unpacked extension

[DCCA]

What

An end-to-end smoke test that launches real Chromium (new headless) with the unpacked dist/ loaded (--load-extension) and exercises the page-side parts of one-click capture that browser automation can drive:

• Extension loads — service worker registers; manifest has no default_popup and includes the downloads permission.
• On-page capture notice — driven through the real injected content script via SB_CAPTURE_BEGIN / SB_SET_OVERLAY / SB_CAPTURE_END: shows (display:flex, correct text), hides cleanly (display:none — the leak fix), and is removed from the DOM.
• Editor page renders — Capture Page and Copy for Claude Code buttons are visible.

How it's wired

• @playwright/test devDep + npm run test:e2e (builds dist/, then playwright test).
• playwright.config.ts (testDir: tests/e2e); vitest.config.ts scopes unit tests to tests/**/*.test.ts so vitest ignores the .spec.ts.
• Playwright artifacts gitignored; command documented in CLAUDE.md.

Deliberately excluded from npm run check and CI — it needs downloaded browsers + new-headless. Run locally after a one-time npx playwright install chromium.

Verification

• npm run test:e2e → 3 passed.
• Unit gate unaffected: npm run check green (vitest still 7 unit files, no e2e), npm audit --audit-level=high → 0 vulnerabilities, format:check clean.

🤖 Generated with Claude Code

[DCCA]

Review (independent subagent + applied fixes)

Verdict: ship. No blockers. Verified by running the gates: npm run test (7 unit files, 54 pass — e2e .spec.ts correctly excluded via vitest.config.ts), typecheck/lint/build clean, npm audit --audit-level=high → 0 vulns, npm run test:e2e → 3 pass. Confirmed e2e is genuinely out of npm run check and CI.

Applied the two worthwhile nits:

• Hardened send() to retry until the content script receives the message (it registers at document_idle, so the first send could race page load) and to throw clearly if it never arrives — folds in the "assert tab exists" suggestion.
• Added vitest.config.ts + playwright.config.ts to tsconfig.json include so typecheck covers them too.

Re-ran after the changes: e2e 3/3, typecheck/lint/unit/format all green.