fix: handle large text binds in DML

[hjianbo]

Summary

This PR fixes Oracle DML execution when a text bind grows beyond 4000 characters.

The failure was reproduced from the EMQX Oracle action write path: an INSERT into an NCLOB payload column works with a small payload, but a later payload larger than 4000 characters can fail when another bind expression follows the payload bind, for example a timestamp expression after the payload value.

The issue is in the driver bind metadata/cursor handling, not in the caller. A cursor prepared for the small text bind shape can be reused for a later large text bind shape, and Oracle can reject the bind or close the connection.

Changes

• Include bind format metadata in the cursor cache key, so incompatible small-text and large-text bind shapes do not reuse the same cursor.
• Merge bind metadata across batch rows so mixed small/large text batches are encoded with a compatible bind format.
• For DML statements where a large text bind is not the trailing bind, internally wrap the statement in a PL/SQL block, reorder only the driver-level bind variables so large CLOB values are sent last, and return SQL%ROWCOUNT as normal affected_rows.
• Keep statements with out parameters on the existing path.

Side Effects

For the large-text/non-trailing-bind DML edge case, a batch may be executed internally row by row to avoid the Oracle protocol failure. The public result shape remains {affected_rows, Total} for successful DML batches.

Tests

• rebar3 compile
• rebar3 ct --suite test/jamdb_oracle_SUITE.erl --group lob_datatypes
• Verified through EMQX Oracle bridge CT for the customer-style write path in EEC-1322.