Add panic-related clippy lints to fortuna

This PR adds a [lints.clippy] section to the fortuna Cargo.toml file to deny clippy lint rules that guard against panics. This helps prevent potential runtime panics in the codebase.

Specifically, the following panic-related lints are denied:

• unwrap_used
• expect_used
• panic
• panic_in_result_fn
• indexing_slicing
• arithmetic_overflow
• unwrap_in_result
• option_unwrap_used
• result_unwrap_used
• todo
• unimplemented
• unreachable
• expect_fun_call
• cast_possible_truncation
• cast_possible_wrap
• cast_sign_loss
• cast_precision_loss
• unchecked_duration_subtraction
• float_arithmetic
• float_cmp
• modulo_one
• integer_division
• try_err

Note on Implementation

Running the pre-commit hooks with these lints enabled shows over 65 lint errors in the codebase. Fixing all of these would require significant refactoring, including:

1. Replacing .unwrap() and .expect() calls with proper error handling
2. Replacing indexing operations with .get() or .get_mut() to avoid potential panics
3. Addressing floating-point arithmetic and casting issues

Test Configuration

Note that these lints will also apply to test code. To exclude tests from these lint rules, code-level attributes should be used in test modules or functions:

#[cfg(test)]
mod tests {
    #[allow(clippy::unwrap_used, clippy::expect_used, clippy::indexing_slicing)]
    #[test]
    fn test_something() {
        // Test code that uses unwrap(), expect(), etc.
    }
}

As requested, I've added the lints but have not made the extensive code changes required to fix all the errors.

Link to Devin run: https://app.devin.ai/sessions/7628ce4c804a45eea59d57847ac320d3

Requested by: Jayant Krishnamurthy