Compile-time exhaustiveness checking for Malli :enum schemas.

Provides macros that emit `case` expressions while verifying at
macro-expansion time that every enum value is handled.

Usage:
  (def Status [:enum :draft :published :archived])

  (enum-case Status status
    :draft     (handle-draft)
    :published (handle-published)
    :archived  (handle-archived))

If a branch is missing, macro expansion fails with a clear error.

Supports:
  - Var-based schema references (symbol pointing to a def)
  - Malli registry lookups (qualified keyword)
  - Inline schema literals (vector)
  - Grouped match values like `(:a :b) expr`
  - Optional default branch via `enum-case*`