style: treefmt main — fix CI formatting check

Full `nix flake check` (CI) runs the treefmt formatting derivation. While the
hive-ci runner was offline (#1221), PRs merged without it, leaving 5 files
unformatted: hive-ag3nt/src/web_ui.rs, hive-c0re/src/bin/hivectl.rs,
hive-c0re/src/knowledge.rs, hive-c0re/src/matrix.rs,
hive-forge/src/verbs/attachment_get.rs. `nix fmt` output, pure formatting.

hive-forge/src/verbs/attachment_get.rs

@@ -80,7 +80,9 @@ fn extract_uuid(input: &str) -> Result<String> {
             .rsplit('/')
             .next()
             .filter(|s| !s.is_empty())
-            .ok_or_else(|| anyhow::anyhow!("hive-forge attachment-get: cannot extract UUID from {input:?}"))?
+            .ok_or_else(|| {
+                anyhow::anyhow!("hive-forge attachment-get: cannot extract UUID from {input:?}")
+            })?
     } else {
         input
     };