chore(e2e): scaffold E2E harness directory and install deps

Add pytest-playwright and pytest-json-report to requirements.txt; create
tests/e2e/ skeleton (modes/, pages/, results/) with __init__.py files and
.gitkeep; add results subdirs to .gitignore.

.gitignore

@@ -49,3 +49,8 @@ demo/seed_demo.py
 # Git worktrees
 .worktrees/
 .env.e2e
+
+# E2E test result artifacts
+tests/e2e/results/demo/
+tests/e2e/results/cloud/
+tests/e2e/results/local/

requirements.txt

@@ -13,6 +13,8 @@ streamlit-paste-button>=0.1.0
 # ── Job scraping ──────────────────────────────────────────────────────────
 python-jobspy>=1.1
 playwright>=1.40
+pytest-playwright>=0.4
+pytest-json-report>=1.5
 selenium
 undetected-chromedriver
 webdriver-manager