Replace Scattered Role Checks with a Three-Level Permission Tree

Developers often scatter inline role checks like if (role === 'admin') across codebases, which becomes difficult to manage as apps grow in complexity. A cleaner approach defines one structured permission tree per role, organized across three levels: page, section, and action (read or write). A single generic function, checkAccess, walks this tree and returns true or false, failing closed whenever a node is missing. Named helper functions like canEditReportsExport wrap the core checker, keeping each permission path defined in exactly one place and usable in nav links, route guards, and UI controls. The pattern suits most CRUD-style applications well, though it has known limitations around attribute-based rules, explicit deny overrides, and large permission matrices.