[Minor] Migrate lua_maps.lua from tableshape to lua_shape

[Minor] Migrate lua_maps.lua from tableshape to lua_shape

Replace tableshape with lua_shape for map configuration schemas:
- Convert ts.shape to T.table
- Convert ts.equivalent(true) to T.literal(true)
- Convert :is_optional() to :optional()
- Convert ts.one_of to T.one_of with proper braces
- Convert ts.enum with :is_optional() to T.enum():optional()
- Convert ts.array_of to T.array

Updates external_map_schema, direct_map_schema, and exports.map_schema.
No functional changes, luacheck passes.