chore: better init and test capabilities

Dockerfile

@@ -18,8 +18,15 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     libyaml-dev \
     libpq-dev \
     socat \
+    chromium \
+    chromium-driver \
     && rm -rf /var/lib/apt/lists/*
 
+# Selenium/Capybara discover Chrome via these env vars.
+# chromium-driver installs chromedriver at /usr/bin/chromedriver.
+ENV CHROME_BIN=/usr/bin/chromium
+ENV CHROMEDRIVER=/usr/bin/chromedriver
+
 # --- rbenv (installed into home volume on first run, via entrypoint) ---
 # RBENV_ROOT points into the home volume so the install persists across rebuilds.
 ENV RBENV_ROOT=/home/coder/.rbenv