test: add Playwright e2e smoke suite for punimtag dev

Add an e2e/ Playwright harness (via @levkin/playkit) that smoke-tests
the public DEV host: login page loads, sign-out never redirects to a
LAN host, FastAPI /health responds, and forgot-password mail lands in
Mailtrap with a public reset link (Kolby #56/#57 regressions).

Wire it into Gitea Actions as a new `e2e` job (self-hosted runner,
Chromium via Playwright), gated behind the existing skip-ci-check.
Add npm root scripts (install:e2e, test:e2e) and gitignore e2e build
artifacts (node_modules, reports, .env).

e2e/.env.example

@@ -0,0 +1,17 @@
+# Public UI (required for host-guard tests)
+PLAYKIT_BASE_URL=https://punimtagdev.levkin.ca
+PLAYKIT_PROJECT=punimtag
+PLAYKIT_ENV=dev
+
+# FastAPI on the DEV LXC (runners on LAN can reach this)
+PLAYKIT_API_BASE_URL=http://10.0.10.121:8000
+
+# Dedicated e2e user — never commit real passwords
+E2E_ADMIN_EMAIL=
+E2E_ADMIN_PASSWORD=
+
+# Mailtrap Email Testing (optional — forgot-password specs skip if unset)
+# MAILTRAP_API_TOKEN=
+# MAILTRAP_ACCOUNT_ID=
+# MAILTRAP_INBOX_ID=
+# E2E_MAIL_TO=   # defaults to E2E_ADMIN_EMAIL