viser v0.4.1

Changed

• Trimmed tokio features — the workspace no longer enables tokio's full
  feature set. Each crate now declares only the features it uses (rt, process,
  io-util, sync, net, macros as needed), dropping unused subsystems
  (fs, time, signal, …) from the dependency graph and leaving the library
  crates leaner for downstream consumers.

Fixed

• Activated a dormant test — viser-complexity's test_analyze_opts_default
  was missing its #[test] attribute and had never run; it is now part of the suite.
• Corrected MSRV in the README project table — it listed 1.85 while the actual
  MSRV (and the badge) is 1.88.
• Removed the unknown clippy::manual_checked_ops lint allow and cleared the
  clippy lint debt that surfaced once warnings became errors.

CI

• clippy now runs with -D warnings, so lint regressions fail the build.
• Added a macOS runner to the test matrix and an MSRV (1.88) build job.
• Added a cargo-deny job that enforces the existing deny.toml
  (advisories, licenses, bans).