lint: fix clippy absolute_paths & disallowed_methods after merge

- Import serde:🇩🇪:Error trait so the `custom` fn pointer uses `D::Error`
  instead of the absolute `serde:🇩🇪:Error::custom` path.
- Import `fabro_api::types::ServerSettings` / `fabro_config::UserSettings`
  directly rather than through absolute paths.
- Gate sync `std::fs::write` fixture setup in new config resolver tests
  with a file-level `#![expect(clippy::disallowed_methods, …)]`.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

lib/crates/fabro-cli/src/commands/config/mod.rs

@@ -9,6 +9,8 @@
 
 use std::io::Write;
 
+use fabro_api::types::ServerSettings;
+use fabro_config::UserSettings;
 use fabro_types::settings::CliNamespace;
 use fabro_types::settings::cli::{CliLayer, OutputFormat};
 use fabro_util::printer::Printer;
@@ -20,8 +22,8 @@ use crate::shared::print_json_pretty;
 
 #[derive(Serialize)]
 struct RenderedConfig {
-    user:   fabro_config::UserSettings,
-    server: fabro_api::types::ServerSettings,
+    user:   UserSettings,
+    server: ServerSettings,
 }
 
 async fn rendered_config(

lib/crates/fabro-client/src/client.rs

@@ -490,16 +490,14 @@ impl Client {
         }
     }
 
-    pub async fn retrieve_resolved_server_settings(
-        &self,
-    ) -> Result<fabro_api::types::ServerSettings> {
+    pub async fn retrieve_resolved_server_settings(&self) -> Result<types::ServerSettings> {
         let url = format!("{}/api/v1/settings", self.base_url());
         let response = self
             .send_http(|http_client| async move { http_client.get(&url).send().await })
             .await?;
 
         response
-            .json::<fabro_api::types::ServerSettings>()
+            .json::<types::ServerSettings>()
             .await
             .context("server returned invalid JSON for server settings")
     }

lib/crates/fabro-config/tests/resolve_cli.rs

@@ -1,3 +1,8 @@
+#![expect(
+    clippy::disallowed_methods,
+    reason = "sync test fixture setup; not on a Tokio path"
+)]
+
 use fabro_config::{parse_settings_layer, resolve_cli_from_file};
 use fabro_types::settings::cli::{CliTargetSettings, OutputFormat, OutputVerbosity};
 use fabro_types::settings::run::AgentPermissions;

lib/crates/fabro-config/tests/resolve_server.rs

@@ -1,3 +1,8 @@
+#![expect(
+    clippy::disallowed_methods,
+    reason = "sync test fixture setup; not on a Tokio path"
+)]
+
 use fabro_config::parse_settings_layer;
 use fabro_config::user::default_storage_dir;
 use fabro_types::settings::server::{

lib/crates/fabro-types/src/settings/server.rs

@@ -10,6 +10,7 @@ use std::net::SocketAddr;
 use std::time::Duration as StdDuration;
 
 use ipnet::IpNet;
+use serde::de::Error as _;
 use serde::{Deserialize, Deserializer, Serialize, Serializer};
 
 use super::duration::Duration as DurationLayer;
@@ -287,7 +288,7 @@ where
     D: Deserializer<'de>,
 {
     let value = String::deserialize(deserializer)?;
-    value.parse().map_err(serde::de::Error::custom)
+    value.parse().map_err(D::Error::custom)
 }
 
 fn serialize_std_duration<S>(value: &StdDuration, serializer: S) -> Result<S::Ok, S::Error>