fix(db): preserve unsigned 64-bit values during parameter binding

[GaspardKirira]

Summary

Fix unsigned 64-bit parameter binding so values greater than INT64_MAX are not silently converted to negative signed values.

The public overload accepting std::uint64_t must remain available.

Current behavior

Statement::bind(std::size_t, std::uint64_t) converts the value to std::int64_t before forwarding it.

DbValue already contains a std::uint64_t alternative, but the current driver implementations do not consistently handle it.

Expected behavior

Unsigned 64-bit values must either:

• be bound losslessly when supported by the backend; or
• fail clearly when a backend cannot represent the value safely.

Silent narrowing must not occur.

Scope

• Stop unconditional signed narrowing in the convenience overload.
• Add explicit std::uint64_t handling to SQLite.
• Add explicit std::uint64_t handling to MySQL.
• Define backend behavior for values above the signed 64-bit range.
• Add boundary-value tests.
• Preserve the existing public DB API.

Suggested files

• modules/db/include/vix/db/core/Drivers.hpp
• modules/db/src/sqlite/SQLiteDriver.cpp
• modules/db/src/mysql/MySQLDriver.cpp
• modules/db/tests/sqlite_driver_test.cpp
• modules/db/tests/mysql_driver_test.cpp

Acceptance criteria

• 0, INT64_MAX, INT64_MAX + 1, and UINT64_MAX are tested.
• No unsigned value is silently converted to a negative value.
• Supported values round-trip correctly.
• Unsupported values produce a clear DBError.
• Existing public overloads remain source-compatible.

Non-goals

This issue does not include:

• arbitrary-precision integers;
• decimal numeric types;
• schema type changes;
• ORM numeric conversion.

Suggested labels

• scope:db
• type:bug
• tests
• help wanted
• status:ready