test(e2e): browser suite for the flows the server tests cannot see

Playwright under e2e/, its own npm project so Meteor never sees the dependency
(.meteorignore keeps the directory out of the bundle — a config file at the app
root is otherwise eagerly loaded into the server and crashes it).

Covers what the phase asked for: sign up / log in, creating a zone from the map
and watching the union get painted on /subscriptions and /zones, removing it
again, commenting on a fire, and switching language. The zone spec is the flow
that froze staging on 2026-07-30 — it passes only if the server is still
answering DDP while the union is recomputed.

docker-compose.e2e.yml is a throwaway stack (Mongo on tmpfs, no named volume) so
the destructive seeds cannot be pointed at anything real by accident;
playwright.config.js refuses to start against the staging or production domains.

i18n.spec.js leaves a test.fixme on a real bug found while writing it: the
language chosen in the profile does not survive a page reload.

e2e/package.json

@@ -0,0 +1,15 @@
+{
+  "name": "tcef-e2e",
+  "private": true,
+  "description": "Browser end-to-end suite for todos-contra-el-fuego-web. Kept out of the app's package.json on purpose: Meteor should never see these dependencies.",
+  "type": "module",
+  "scripts": {
+    "test": "playwright test",
+    "test:headed": "playwright test --headed",
+    "report": "playwright show-report",
+    "install-browsers": "playwright install --with-deps chromium"
+  },
+  "devDependencies": {
+    "@playwright/test": "^1.49.1"
+  }
+}