fix(lint): resolve E410 doc style issues and apply dune fmt

Add missing periods to doc comments, fix [name] format mismatches,
rename camelCase variant constructors to snake_case in hooks.ml,
and apply dune fmt formatting.

lib/cache.mli

···
   type t
 
   val equal : t -> t -> bool
+  (** Equality function. *)
+
   val hash : t -> int
+  (** Hash function. *)
 end
 
 module type S = sig

test/test_cache.mli

···
 val suite : string * unit Alcotest.test_case list
+(** Test suite. *)