feat(container): add pinned Playwright Docker image and compose stack for Matomo bootstrap

- Add Dockerfile based on pinned Playwright image (v1.46.0-jammy) for reproducible browser runtime
- Introduce docker-compose stack (MariaDB + Matomo + one-shot bootstrap)
- Extend Makefile with container image and stack management targets
- Add env.sample for environment-driven bootstrap configuration
- Relax Playwright dependency to >=1.46.0 to keep Nix builds compatible
- Add E2E test ensuring docker-compose bootstrap exits with 0 and prints token

env.sample

@@ -0,0 +1,29 @@
+# --- REQUIRED ---
+MATOMO_URL=http://127.0.0.1:8080
+MATOMO_ADMIN_USER=administrator
+MATOMO_ADMIN_PASSWORD=AdminSecret123!
+MATOMO_ADMIN_EMAIL=administrator@example.org
+
+# --- OPTIONAL ---
+# Description for the app-specific token
+MATOMO_TOKEN_DESCRIPTION=ansible-bootstrap
+
+# Timeout (seconds)
+MATOMO_TIMEOUT=30
+
+# Debug logs to stderr (stdout stays token-only)
+# MATOMO_DEBUG=1
+
+# If set, bootstrap will NOT create a new token
+# but return this one instead (idempotent runs)
+# MATOMO_BOOTSTRAP_TOKEN_AUTH=0123456789abcdef...
+
+# Values used by the recorded installer flow
+MATOMO_SITE_NAME=Matomo
+MATOMO_SITE_URL=http://127.0.0.1:8080
+MATOMO_TIMEZONE=Germany - Berlin
+
+# Playwright knobs (usually not needed)
+# MATOMO_PLAYWRIGHT_HEADLESS=1
+# MATOMO_PLAYWRIGHT_NAV_TIMEOUT_MS=60000
+# MATOMO_PLAYWRIGHT_SLOWMO_MS=0