feat(plc): dynamic PLC testing via ephemeral soft-PLC (#193)

compliance-agent/src/config.rs

@@ -1,3 +1,4 @@
+use compliance_core::config::PlcRuntimeConfig;
 use compliance_core::AgentConfig;
 use secrecy::SecretString;
 
@@ -63,5 +64,28 @@ pub fn load_config() -> Result<AgentConfig, AgentError> {
         pentest_imap_password: env_secret_opt("PENTEST_IMAP_PASSWORD"),
         admin_api_token: env_secret_opt("ADMIN_API_TOKEN"),
         tenant_registry_url: env_var_opt("TENANT_REGISTRY_URL"),
+        plc_runtime: load_plc_runtime_config(),
     })
 }
+
+/// Build the ephemeral soft-PLC provisioning config from the environment,
+/// falling back to [`PlcRuntimeConfig::default`] for any unset knob. Disabled
+/// unless `PLC_RUNTIME_ENABLED` is truthy — it requires Docker access.
+fn load_plc_runtime_config() -> PlcRuntimeConfig {
+    let d = PlcRuntimeConfig::default();
+    PlcRuntimeConfig {
+        enabled: env_var_opt("PLC_RUNTIME_ENABLED")
+            .map(|v| v == "1" || v.eq_ignore_ascii_case("true"))
+            .unwrap_or(d.enabled),
+        image: env_var_opt("PLC_RUNTIME_IMAGE").unwrap_or(d.image),
+        network: env_var_opt("PLC_RUNTIME_NETWORK").unwrap_or(d.network),
+        memory: env_var_opt("PLC_RUNTIME_MEMORY").unwrap_or(d.memory),
+        cpus: env_var_opt("PLC_RUNTIME_CPUS").unwrap_or(d.cpus),
+        max_lifetime_secs: env_var_opt("PLC_RUNTIME_MAX_LIFETIME_SECS")
+            .and_then(|v| v.parse().ok())
+            .unwrap_or(d.max_lifetime_secs),
+        openplc_user: env_var_opt("PLC_RUNTIME_OPENPLC_USER").unwrap_or(d.openplc_user),
+        openplc_password: env_secret_opt("PLC_RUNTIME_OPENPLC_PASSWORD")
+            .unwrap_or(d.openplc_password),
+    }
+}