chore: roll up security migration - #161

This revision bumps the workspace `tinybus` / `tinybus-module` requirements to `>=0.3.12, <0.4` (Cargo.lock already resolves 0.3.12) and relaxes `expect(missing_docs, ...)` to `allow(missing_docs)` in the generated ABI module. Both are small, self-consistent changes; nothing here fails or regresses for a reachable input, and the PR body's claim of a compatibility bump with no user-facing change matches the diff.

No findings.