v0.4.5: tolerate missing [nginx] section and fail gracefully on bad config

The `nginx` field in `Config` was required, so a wolfproxy.toml without
an `[nginx]` section (as produced by wolfstack's restore button) caused
`toml::from_str` to fail with "missing field nginx", which the `.expect`
turned into a panic + SIGABRT + coredump in the journal. Other working
installs have always had `[nginx]` written by an earlier path; this only
surfaced once restore wrote a stripped-down config.

- Add `#[serde(default)]` to the `nginx` field — `NginxConfigSettings`
  already has a `Default` impl returning `config_dir = "/etc/nginx"`.
- Replace `.expect` with a graceful `eprintln!` + `exit(1)` so a bad
  config produces a readable journal line instead of a coredump.

Co-Authored-By: CodeWolf <paul@wolf.uk.com>
Co-Authored-By: Wolf Software Systems Ltd <paul@wolf.uk.com>

Author: Paul C

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "wolfproxy"
-version = "0.4.4"
+version = "0.4.5"
 edition = "2021"
 description = "A Rust-based nginx proxy replacement that reads nginx configuration files"
 authors = ["Wolf Software Systems Ltd"]

src/main.rs

@@ -134,6 +134,7 @@ fn load_ssl_keys(cert_path: &Path, key_path: &Path) -> anyhow::Result<CertifiedK
 #[derive(Debug, Clone, Deserialize)]
 struct Config {
     server: ServerConfig,
+    #[serde(default)]
     nginx: NginxConfigSettings,
     #[serde(default)]
     monitoring: MonitoringConfig,
@@ -300,7 +301,14 @@ password = "admin"
         }
     };
 
-    let config: Config = toml::from_str(&config_str).expect("Failed to parse wolfproxy.toml");
+    let config: Config = match toml::from_str(&config_str) {
+        Ok(c) => c,
+        Err(e) => {
+            eprintln!("Failed to parse wolfproxy.toml: {e}");
+            eprintln!("Hint: ensure the file contains at minimum a [server] section with `host = \"0.0.0.0\"`. The [nginx], [monitoring], and [firewall] sections are optional and will use defaults if omitted.");
+            std::process::exit(1);
+        }
+    };
 
     info!("Loading nginx configuration from {}", config.nginx.config_dir);