A landmark legal settlement with State Farm Fire & Casualty Co. promises to jump-start the rebuilding process for thousands of Mississippi homeowners devastated by Hurricane Katrina, but critics warn the deal could hurt many of Mississippi’s Gulf Coast residents. That’s because the multimillion dollar accord threatens to make the hurricane-ravaged coast an even less attractive market for major insurers that already are reluctant to renew policies or write new coverage in the storm’s aftermath, industry experts said Wednesday.