sql: readable human output — table by default, plus --vertical and \G support

[mcrauwel]

What

pscale sql human output printed each row with Go's %v map formatting — unordered keys, map[...] syntax — which is unreadable for wide results such as SHOW REPLICA STATUS. And a trailing \G, which mysql users reach for out of habit, was sent to the server verbatim and rejected with Error 1105: syntax error.

This PR makes the human format render results the way the mysql client does:

• Table by default: rows render as an aligned ASCII table, columns in the order the server returned them, NULL shown as NULL.
• --vertical flag: one column per line with right-aligned names (*************************** 1. row *************************** style), for wide rows.
• Trailing \G / \g: stripped client-side before the query is sent (they are mysql client terminators, not SQL). \G also enables vertical output, matching mysql semantics; \g is just stripped.

JSON and CSV output formats are unchanged.

Before

❯ pscale sql mydb main --org myorg --query "show replica status\G" --replica
Error: Error 1105 (HY000): syntax error at position 21 near 'status'
❯ pscale sql mydb main --org myorg --query "show replica status" --replica
Returned 1 row(s)
1: map[Auto_Position:1 Channel_Name: Connect_Retry:10 Exec_Source_Log_Pos:505711876 ...]

After

❯ pscale sql mydb main --org myorg --query "show replica status\G" --replica
*************************** 1. row ***************************
             Replica_IO_State: Waiting for source to send event
                  Source_Host: 10.x.x.x
                  Source_User: vt_repl
                  ...
Returned 1 row(s)

Tests

• stripVerticalTerminator: trailing \G/\g with/without whitespace, mid-string \G untouched, bare terminator
• renderTable: golden-string check for column order, alignment, borders, NULL; multi-line values (GTID sets) sized to their longest line without breaking the table
• renderVertical: golden-string check for right-aligned names and row headers
• printHumanResult: rows-affected, zero-rows, table, and vertical branches; asserts no map[ in output
• --vertical flag registration

🤖 Generated with Claude Code

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