The a2a merge (d0d8e7f) landed with a handful of pre-existing rustfmt
diffs that were failing `cargo fmt --all --check` in CI. Pure whitespace
reformatting from `cargo fmt --all`; no semantic changes. Files touched:
mcp_door.rs, quota.rs, routes/a2a.rs, routes/world.rs, runtime_provision.rs,
chat_repos.rs test, and tools/chat.rs.