[CBRD-26961] Add client->server stream transport protocol (COPY first consumer)

[hgryoo]

http://jira.cubrid.org/browse/CBRD-26961

Purpose

Add JDBC support for the shared client→server byte-stream transport introduced
in [CBRD-26961]. Its first consumer is COPY <table> FROM STDIN; the transport is
consumer-agnostic so later consumers (internal-LOB input) reuse the same wire path.
JDBC had no COPY/stream support, so this is net-new.

Implementation

• UFunctionCode: STREAM_SEND_DATA(45) / STREAM_END(46), matching the server
  and CCI wire ordinals (after SET_CAS_CHANGE_MODE(44)).
• UConnection: streamSendData(byte[], int, int) / streamEnd() jci request
  methods, modeled on lobWrite(). streamEnd() returns the number of rows loaded.
• CUBRIDConnection (public API): streamData(byte[]) / streamData(byte[], int, int)
  and streamEnd(). After executing COPY ... FROM STDIN, send the encoded payload
  with streamData() and finish with streamEnd().

Usage

CUBRIDConnection con = ...;
con.createStatement().execute("COPY t FROM STDIN WITH (FORMAT BINARY)");
con.streamData(encodedRows);   // repeat as needed
int rows = con.streamEnd();

Remarks

• Build-verified (ant / JDK 1.8): BUILD SUCCESSFUL, driver jar produced.
• Row/payload encoding is the application's responsibility (binary/CSV), same as CCI.
• Pairs in lockstep with the server PR ([[CBRD-26961] COPY FROM STDIN over a shared client-server binary stream transport cubrid#7343]) and the CCI PR
  ([[CBRD-26961] Add client->server stream transport protocol (COPY first consumer) cubrid-cci#105]).