AggregateKind (4 values), MemoryDim (7), AccessPattern (5),
Frequency (7), RecommendedDirection (4). All Literal types
for stable postfix DSL output (string-valued, no enum-name
lookup table needed in the parser).
5 unit tests passing. The 9 supporting dataclasses + the
AggregateProfile central artifact go in Tasks 1.2-1.10.