[scorecard][utf] Implement createEntities subset used by official suites

[midagedev]

Parent Epic: #98

Why

unsupported UTF operation: createEntities is a recurring blocker in official suites.

Scope

• Implement minimum createEntities subset required by current pinned official specs.
• Restrict to deterministic, in-process compatible entity types.
• Add explicit unsupported contract for out-of-scope entity kinds.

Success Criteria

• createEntities unsupported reason count drops materially in rerun artifacts.
• Runner behavior is deterministic and documented.

Priority

P1/P2 boundary (start once #99 identifies exact entity cases).

[midagedev]

Merged in PR #105.\n\nValidation snapshot (local UTF rerun across crud/transactions/sessions with pinned specs):\n- imported: 480\n- unsupported: 526\n- mismatch: 84\n- error: 0\n\n unsupported reason is no longer present in top unsupported reason buckets, and transactions-unified imported coverage increased from 0 (baseline ledger run 22339640205) to 162.\n\nThis issue scope (createEntities subset support) is satisfied.

[midagedev]

Clarification: the removed unsupported bucket is unsupported UTF operation: createEntities.