Enable clippy::unnecessary_wraps lint

[tupe12334]

Summary

Enable the clippy::unnecessary_wraps lint by adding it to the [lints.clippy] table in core/Cargo.toml.

This continues the project's incremental lint-ratcheting policy (one lint promoted to deny per PR).

What the lint catches

clippy::unnecessary_wraps flags functions that always return Ok(...) (or Some(...)) and never return Err/None, yet declare a Result<T> / Option<T> return type. The wrapper type is dead weight: it forces every caller to handle an error case that can never occur.

Why it improves code quality

• Honest signatures — the return type should reflect what the function can actually do. A function that never fails should not advertise fallibility.
• Less caller boilerplate — removes pointless ?, .unwrap(), and match Ok/Err arms at call sites.
• Smaller error surface — fewer spurious error paths to reason about and test.

Current state

Baseline cargo clippy --all-targets is clean. Enabling this lint surfaces exactly one real violation:

• core/src/bin/main.rs — run_validate() returns io::Result<bool> but never returns Err; all branches return Ok(...).

The accompanying PR enables the lint and fixes that single function (returning plain bool), simplifying the validate command's call site and the related tests.

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This issue was opened by the "Clippy lint improvements → issue + PR (Rust repos) → Slack" routine of moadim.