Fix contextual integer literal checks in call arguments

[HarperZ9]

Summary

• Enforce concrete integer literal range diagnostics for selected call parameter types without replacing argument-position coercion.
• Preserve &mut T to &T argument coercion for direct calls, impl methods, and overloaded calls.
• Add CLI regressions for signed-min i64 argument spelling and the coercion compatibility path.

Validation

• cargo test --manifest-path compiler/Cargo.toml --quiet
• cargo fmt --manifest-path compiler/Cargo.toml -- --check
• git diff --check