feat(mysql): complete Community MySQL product parity

[openai0229]

Summary

• complete the Community MySQL milestone across datasource and SSH management, Console, metadata, DML and DDL, routines, transfer, account authorization, schema diff, workspace, dashboard, AI, CLI, MCP, HTTP, and desktop IPC
• use the native mysql_async path for MySQL 8.4 while keeping Java compatibility lazy and on demand
• pin the validated Community compatibility sources and document the final parity boundary

Verification

• make verify
• make native-mysql-direct-integration MYSQL_TEST_USER=root MYSQL_TEST_PASSWORD=root
• make community-product-mysql-integration MYSQL_TEST_USER=root MYSQL_TEST_PASSWORD=root
• real MySQL concurrent SSH tunnel integration
• strict Clippy, Rust workspace tests, Java tests, Rust-Java IPC/JDBC tests, frontend tests/typecheck/build, Desktop checks
• actionlint, diff checks, fixture cleanup checks, and Chat2DB knowledge lint
• independent clean detached-worktree verification of the pinned H2 baseline

Release behavior

This PR runs the regular CI workflow only. macOS packaging remains manual and is not triggered by this branch or PR.

Fixes #14