refactor(core): introduce unified native driver SPI

[openai0229]

Summary

• introduce a runtime-selected native Rust driver registry
• split connection, query, metadata, table, routine, transfer, dialect, administration, and schema-diff capabilities
• route the existing MySQL implementation through neutral Core contracts
• isolate legacy HTTP/IPC and JDBC compatibility adapters from the native SPI

Verification

• make verify
• workspace tests: 780 passed, 4 ignored
• strict clippy passed
• knowledge lint passed