docs: add Tailscale MySQL middleware guide

cai

2026-07-02 758dafeab0836ad6a8959bb3fefcdcaeb69a67d8

 scripts/kline_front_incremental_sync.py

@@ -99,9 +99,10 @@
        extra.extend(["--batch", "--raw"])
    if skip_column_names:
        extra.append("--skip-column-names")
    cmd = mysql_cmd(conn, extra + ["-e", sql])
    cmd = mysql_cmd(conn, extra)
    proc = subprocess.run(
        cmd,
        input=sql,
        text=True,
        capture_output=True,
        env=mysql_env(conn),