[Proposal] CLI: Switch table output to kubectl-style format (no borders)

[renuka-fernando]

Summary

• Replace bordered ASCII table output (+---+, | |) with kubectl-style whitespace-aligned columns
• Remove all border characters (+, -, |) from table rendering
• Use left-aligned columns padded with spaces and a 3-space gap between columns
• Only the shared table rendering utility needs to change; all callers are unaffected

Motivation

• The current bordered ASCII table format (+------+-------+) is visually heavy and inconsistent with the kubectl, docker, gh, and helm CLI conventions that Go CLI users expect
• Every major CLI tool in the Kubernetes and cloud-native ecosystem uses unbordered, whitespace-aligned tables as the default output format
• Bordered tables consume more horizontal space due to | pipe characters and +---+ separators on every row, making output harder to scan in narrow terminal windows

Proposal

• Change the CLI's shared table rendering to produce kubectl-style output: uppercase headers, left-aligned columns, 3-space gaps, no borders
• The column-width computation logic stays the same — only the border rendering changes
• All commands that display tables (ap gateway list, ap gateway rest-api list, ap gateway mcp list) will automatically pick up the new format with no changes needed

Examples

Before (ap gateway list):

+------+-----------------------+-------+
| NAME | SERVER                | AUTH  |
+------+-----------------------+-------+
| dev  | http://localhost:9090 | basic |
+------+-----------------------+-------+

After (ap gateway list):

NAME   SERVER                  AUTH
dev    http://localhost:9090   basic

Before (ap gateway rest-api list):

+----------------+--------------+---------+-------------------+----------+--------------------------------+
| ID             | DISPLAY_NAME | VERSION | CONTEXT           | STATUS   | CREATED_AT                     |
+----------------+--------------+---------+-------------------+----------+--------------------------------+
| weather-api-v1 | Weather-API  | v1.0    | /weather/$version | deployed | 2026-03-10T05:39:55.370590516Z |
+----------------+--------------+---------+-------------------+----------+--------------------------------+

After (ap gateway rest-api list):

ID               DISPLAY_NAME   VERSION   CONTEXT             STATUS     CREATED_AT
weather-api-v1   Weather-API    v1.0      /weather/$version   deployed   2026-03-10T05:39:55.370590516Z

References

• kubectl output conventions - Reference for table output style used by the Kubernetes CLI

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Document Version: 1.0
Last Updated: 2026-03-13
Status: Proposed

[renuka-fernando]

This is completed.