Set up Rails 8 application foundation

- Generate Rails 8.1 app with PostgreSQL and TailwindCSS
- Add docker-compose.yml (postgres:17) for local database
- Configure database.yml to connect to Dockerized Postgres via env vars
- Add Pages#home root route, application layout, and navbar partial

config/storage.yml

@@ -0,0 +1,27 @@
+test:
+  service: Disk
+  root: <%= Rails.root.join("tmp/storage") %>
+
+local:
+  service: Disk
+  root: <%= Rails.root.join("storage") %>
+
+# Use bin/rails credentials:edit to set the AWS secrets (as aws:access_key_id|secret_access_key)
+# amazon:
+#   service: S3
+#   access_key_id: <%= Rails.application.credentials.dig(:aws, :access_key_id) %>
+#   secret_access_key: <%= Rails.application.credentials.dig(:aws, :secret_access_key) %>
+#   region: us-east-1
+#   bucket: your_own_bucket-<%= Rails.env %>
+
+# Remember not to checkin your GCS keyfile to a repository
+# google:
+#   service: GCS
+#   project: your_project
+#   credentials: <%= Rails.root.join("path/to/gcs.keyfile") %>
+#   bucket: your_own_bucket-<%= Rails.env %>
+
+# mirror:
+#   service: Mirror
+#   primary: local
+#   mirrors: [ amazon, google, microsoft ]