feat(mysql-dual-conn): add a FLOAT/DOUBLE/BIGINT UNSIGNED fidelity fixture

[slayerjain]

Describe the changes that are made

Adds the fixture that would have caught keploy/keploy#4426, where keploy read MySQL FLOAT and DOUBLE result-set columns with a numeric conversion instead of an IEEE-754 reinterpret. A column holding 9.99 was recorded as 1.0926057e+09 (FLOAT) and 4.621813488089437e+18 (DOUBLE). The corruption happened at record time, so it survived re-recording and replay asserted against a value the database never returned.

Nothing in the e2e suite round-tripped a real typed row through record and replay, which is why the defect went unnoticed.

init.sql — a numeric_fidelity table with FLOAT, DOUBLE and BIGINT UNSIGNED columns, seeded with 9.99 plus sign, zero, whole and subnormal cases. The BIGINT UNSIGNED values above MaxInt64 cover the neighbouring defect: they have no lossless float64 form, so a mock format that routes them through one collapses distinct rows onto the same number.

QueryController — two endpoints:

Endpoint	Covers
GET /api/oms/numerics	binary-protocol result-set decode (FLOAT + DOUBLE + BIGINT UNSIGNED)
GET /api/oms/float-param/{v}	COM_STMT_EXECUTE FLOAT parameter decode, and the matcher's mixed-width float comparison

Both bind a parameter deliberately. Without one, JdbcTemplate issues a plain Statement, Connector/J sends COM_QUERY, and MySQL answers with a text result set whose values are all length-encoded strings — which never touches the binary decode this fixture exists to cover. The OMS datasource already runs with useServerPrepStmts=true, so a bound parameter is all it takes.

Verification

Run locally against keploy 1b6ead43 (buggy) and against the #4426 fix:

	buggy keploy	fixed keploy
recorded price_f	1.0926057e+09	9.99
recorded ratio_d	4.621813488089437e+18	9.99
recorded big_u	—	18446744073709551615
replay	4/6, FAILED	6/6, PASSED

Both the YAML and JSON storage formats were exercised.

Consumer

The keploy-side PR wires these endpoints into .github/workflows/test_workflow_scripts/java/mysql_dual_conn/java-linux.sh, gated so only the record_build_replay_build matrix cell calls them — the fix has to be present in both binaries, so the cross-version cells self-skip.

This PR needs to merge first, otherwise the keploy-side guard fails on endpoints that do not exist yet.