Fix --format yaml and toml output

[realrajaryan]

• Closes [Bug]: Several commands accept --format yaml but emit table or plain text #1528.

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation update

Motivation and Context

Several commands (builder status, image list, stats, system df, system status) advertised --format yaml and --format toml but only handled json, and every other format fell through to the table. With this PR, we now route them through one shared renderer with an exhaustive switch over the format enum, so a missing format would now be a compile error, and not just fail silently.

Few more things to note:

• Since TOML has no top level array, TOML output now wraps list payloads under an items key, bec otherwise it was returning nothing for lists.
• stats now prints one static result for machine readable formats instead of opening its live table view.
• builder status now returns an empty list for json/yaml/toml when no builder is running, instead of the unparseable "builder is not running" text. The table view keeps the message.
• with -q and no builder it now exits 0 with no output, earlier it exited non-zero.

Testing

• Tested locally
• Added/updated tests
• Added/updated docs

[github-actions]

Code Coverage

Tier	Line Coverage
Unit	34.68%
Integration	19.73%
Combined	53.79%