feat(01-01): create configuration infrastructure

- AppConfig, ServerConfig, DatabaseConfig case classes
- zio-config-magnolia for automatic Config derivation
- HOCON application.conf with env variable overrides
- Server: host/port with SERVER_HOST/SERVER_PORT overrides
- Database: host/port/database/user/password with DB_* overrides

summercms/resources/application.conf

@@ -0,0 +1,19 @@
+server {
+  host = "0.0.0.0"
+  host = ${?SERVER_HOST}
+  port = 8080
+  port = ${?SERVER_PORT}
+}
+
+database {
+  host = "localhost"
+  host = ${?DB_HOST}
+  port = 5432
+  port = ${?DB_PORT}
+  database = "summercms"
+  database = ${?DB_NAME}
+  user = "summercms"
+  user = ${?DB_USER}
+  password = "summercms"
+  password = ${?DB_PASSWORD}
+}

summercms/src/config/AppConfig.scala

@@ -0,0 +1,64 @@
+package config
+
+import zio.Config
+import zio.config.magnolia.deriveConfig
+
+/** Server configuration
+  *
+  * @param host
+  *   Server bind host
+  * @param port
+  *   Server bind port
+  */
+final case class ServerConfig(
+    host: String,
+    port: Int
+)
+
+object ServerConfig {
+  given config: Config[ServerConfig] = deriveConfig[ServerConfig]
+}
+
+/** Database configuration
+  *
+  * @param host
+  *   Database host
+  * @param port
+  *   Database port
+  * @param database
+  *   Database name
+  * @param user
+  *   Database user
+  * @param password
+  *   Database password
+  */
+final case class DatabaseConfig(
+    host: String,
+    port: Int,
+    database: String,
+    user: String,
+    password: String
+)
+
+object DatabaseConfig {
+  given config: Config[DatabaseConfig] = deriveConfig[DatabaseConfig]
+}
+
+/** Application configuration
+  *
+  * Composed from server and database configurations. Uses zio-config-magnolia for automatic
+  * derivation.
+  *
+  * @param server
+  *   Server configuration
+  * @param database
+  *   Database configuration
+  */
+final case class AppConfig(
+    server: ServerConfig,
+    database: DatabaseConfig
+)
+
+object AppConfig {
+  given config: Config[AppConfig] = deriveConfig[AppConfig]
+}