style: rustfmt the blob-removal code (fix the CI fmt gate)

The blob-removal commit (6b4c4dc) failed CI's fmt gate — long assert! lines
and a doc comment that stock rustfmt wraps. No behaviour change; just
`cargo fmt`. Verified via `nix develop -c cargo fmt --check`.

src/runtime.rs

@@ -180,9 +180,10 @@ pub async fn run(args: Args) -> Result<()> {
     // force a `.db` rebuild after the v1→v2 migration converts it to text
     // (the stale `.db` keeps a `STRICT … BLOB` engine column + `"blob"`
     // metadata that load otherwise uses as-is).
-    let had_blob_column = std::fs::read_to_string(project.path().join(crate::project::PROJECT_YAML))
-        .map(|b| crate::persistence::migrations::body_declares_blob_column(&b))
-        .unwrap_or(false);
+    let had_blob_column =
+        std::fs::read_to_string(project.path().join(crate::project::PROJECT_YAML))
+            .map(|b| crate::persistence::migrations::body_declares_blob_column(&b))
+            .unwrap_or(false);
     let migrate_registry = crate::persistence::migrations::MigratorRegistry::production();
     let migration_outcome = crate::persistence::migrations::ensure_project_yaml_migrated(
         project.path(),