feat(server): add clap-derive Config (args + env)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

crates/server/src/config.rs

@@ -0,0 +1,21 @@
+use clap::Parser;
+
+/// Runtime configuration, sourced from CLI arguments and environment variables.
+#[derive(Debug, Clone, Parser)]
+#[command(version, about = "Collection management system server")]
+pub struct Config {
+    /// PostgreSQL connection string.
+    #[arg(long, env = "DATABASE_URL")]
+    pub database_url: String,
+
+    /// Address to bind the HTTP server to.
+    #[arg(long, env = "BIND_ADDR", default_value = "0.0.0.0:8080")]
+    pub bind_addr: String,
+
+    /// User-facing application name (OpenAPI title, page title, …).
+    ///
+    /// Defaults to a neutral name; set this to the real product name at deploy
+    /// time. The product name must never be hardcoded in source.
+    #[arg(long, env = "APP_NAME", default_value = "Collection Management System")]
+    pub app_name: String,
+}

crates/server/src/lib.rs

@@ -1 +1,5 @@
 //! Server wiring: configuration and startup.
+
+mod config;
+
+pub use config::Config;

crates/server/tests/config.rs

@@ -0,0 +1,17 @@
+use clap::Parser;
+use server::Config;
+
+#[test]
+fn parses_from_args_with_defaults() {
+    let cfg = Config::try_parse_from(["server", "--database-url", "postgres://localhost/test"])
+        .expect("should parse");
+
+    assert_eq!(cfg.database_url, "postgres://localhost/test");
+    assert_eq!(cfg.bind_addr, "0.0.0.0:8080");
+    assert_eq!(cfg.app_name, "Collection Management System");
+}
+
+#[test]
+fn database_url_is_required() {
+    assert!(Config::try_parse_from(["server"]).is_err());
+}