feat(skill): add Playwright skill (E2E testing + scraping + headless browsing) (#264)

Add ONE tool skill for Playwright: SKILL.md covering E2E test authoring,
selector robustness, network interception/mocking, parallel workers, CI
integration, scraping/headless patterns, accessibility snapshot checks, and
headed debugging; scripts/pwrun (agent-first smoke harness with --json,
fixture-tested); templates/ test-suite scaffold; eight dated references; a
schema-valid evals/evals.json (6 cases); a human-facing README; reverse
routing from qa-methodology and frontend-engineering; top-level README index
entry; and regenerated catalogs (llms.txt, marketplace, codex).

Closes #244.

Co-authored-by: factory-droid[bot] <138933559+factory-droid[bot]@users.noreply.github.com>

.claude-plugin/marketplace.json

@@ -671,6 +671,15 @@
       "strict": false,
       "description": "Use this skill when building or operating internal developer platforms: infrastructure as code, CI/CD, container orchestration, service networking, secrets, and observability. Do not use it to define release process, promotion, rollout, or rollback policy; use release-engineering for that delivery model."
     },
+    {
+      "name": "playwright",
+      "source": "./",
+      "skills": [
+        "./playwright"
+      ],
+      "strict": false,
+      "description": "Operate Playwright for browser automation end to end: author and debug E2E test suites (robust locators, network interception and mocking, parallel workers, accessibility snapshot checks), wire them into CI, and drive headless browsing and scraping with an extract -> validate -> save loop. Use when writing, running, fixing, or scraping with Playwright, when a Playwright CI failure or JSON report needs triage, or when the bundled pwrun script should analyze a run. Do not use for QA strategy or test framework selection (route to qa-methodology), for frontend component or architecture design (route to frontend-engineering), or for Cloudflare/DDoS-GUARD challenge bypass (use flaresolverr)."
+    },
     {
       "name": "privacy-engineering",
       "source": "./",