A single Soroban transaction emitting >3,276 events would exceed
SQLite's SQLITE_MAX_VARIABLE_NUMBER limit (32,767) since each event
uses 10 bind variables in the INSERT statement. This caused crashes
for transactions with ~4K events.

Batch insertableEvents into chunks of 1,000 per INSERT (10,000 bind
variables) to stay well within the limit. All batches complete before
InsertEvents returns.

Add TestInsertEventsBatchingExceedsLimit to verify a single transaction
with 5,000 operation events inserts successfully.

Add TestInsertEventsBatchingExceedsLimit which creates a single
transaction with 5,000 operation events (5,003 total with tx-level
events), inserts, commits, reads back via GetEvents, and asserts
the exact count matches.

Also fix ledgerCloseMetaWithEvents helper to include a valid
TransactionResult so InsertLedger serialization succeeds.

…ounts

Cover 0, 1, 10, 1000, 3000, and 5000 op-level events to exercise
zero-event no-op, single batch, and multi-batch code paths in
InsertEvents. Each subtest inserts, commits, reads back via GetEvents,
and asserts the exact expected count (numOpEvents + 3 tx-level events).