Fix const-tuple printer misclassifying numeric field ids as object types

[ASDAlexander77]

Summary

• isObjectShapedTuple only checked field.id for non-null, so an all-numeric-id ConstTupleType (array-mode literal-type tuples like [1, 2, 3], which use an IntegerAttr id to record position) was misprinted as an object type ({0: 1, 1: 2}) instead of a tuple ([1, 2, 3]). Restricted the check to name-like ids (StringAttr/FlatSymbolRefAttr).
• Added docs/tuple-object-shape-ambiguity-design.md, documenting a deeper, still-open ambiguity found while investigating this: named-element tuples and object/type-literal fields both produce all-StringAttr ids, so the printer cannot always tell them apart from field-id kind alone. Proposed for later review, not implemented.
• Unrelated tag-script version bump (v79→v80) included from local working tree.

Test plan

• Existing suite (no behavior change expected for named-field/object printing; only affects numeric-id const tuples)