Fix the gate findings in the prune change

Clippy's absolute-paths lint on the rendered prune error, the sync
directory reads the prune test documents, and a redundant rustdoc link.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

lib/apps/fabro-server/src/server.rs

@@ -97,7 +97,7 @@ use fabro_types::{
     RunControlAction, RunId, RunRunnableSource, RunStatus, RunStatusKind, RunStreamItem,
     RunStreamItemKind, SandboxProviderKind, ServerSettings, SuccessReason,
 };
-use fabro_util::error::{SharedError, render_compact_with_causes};
+use fabro_util::error::{SharedError, collect_chain, render_compact_with_causes};
 use fabro_util::version::FABRO_VERSION;
 use fabro_variable::{Error as VariableError, VariableStore};
 use fabro_vault::{SecretStore, SecretStoreError, SecretType, Vault};
@@ -2915,7 +2915,7 @@ async fn delete_run_sandbox_resource(
             }
         }
         Err(error) => {
-            let message = fabro_util::error::collect_chain(&error).join(": ");
+            let message = collect_chain(&error).join(": ");
             if force || delete_started {
                 tracing::warn!(
                     run_id = %id,

lib/components/fabro-petri/src/prune.rs

@@ -13,7 +13,7 @@
 //! and each provider removes its sandbox's managed workspace, a host
 //! workspace under the run directory included.
 //!
-//! The runtime a prune runs on is the run's as [`engine`](crate::engine)
+//! The runtime a prune runs on is the run's as [`engine`]
 //! assembles it, reduced to what a prune reads: the store, the run key, the
 //! run directory (where Petri's host registry and action-host markers are)
 //! and the sandbox backend. No step registry, frontend or model client

lib/components/fabro-petri/tests/prune.rs

@@ -6,6 +6,11 @@
 //! The run takes its scope through the sandbox-driver host plugin, so the
 //! test skips, and says why, when the executable is not found.
 
+#![expect(
+    clippy::disallowed_methods,
+    reason = "the test reads the run directory with sync std::fs between awaits"
+)]
+
 mod support;
 
 use std::path::PathBuf;