Tint: more colors or a custom hex value

[dellink]

Follow-up to #835, where the request said "Start with the fixed set. Free-form hex values can come later if there is demand." Here is the demand.

The Tint submenu and agtermctl session tint / workspace tint accept seven fixed colors: red, orange, yellow, green, blue, purple, gray. With more than seven workspaces or projects the colors run out and two unrelated workspaces end up looking the same.

Ideas, any of which would help:

• a wider built-in palette (teal, pink, brown, indigo, mint, …);
• a custom #rrggbb value in the CLI and a color well in the menu, the way session status --color already takes one;
• a user-defined palette in a config file so the menu lists the user's own named colors.

Read-back via tree's tint field would then carry the hex or the custom name. agterm 0.40.0 (c63e515).

[umputun]

added in #890, in master now and coming with the next release. The palette has twelve named colors: teal, pink, brown, indigo and mint join the original seven, all macOS system colors that follow light and dark mode. Any other color goes through agtermctl as a #rrggbb hex:

agtermctl session tint teal --target "$AGTERM_SESSION_ID"
agtermctl workspace tint '#3a7bd5' --on icon,name --target active
agtermctl session new --name prod-db --tint '#c0392b' --tint-on icon,name

a hex tint stays the same in light and dark mode, and tree --json reads it back as lowercase #rrggbb. The row menu has no color picker. A row tinted with a hex shows a checked "Custom #rrggbb" entry there, and picking a named color replaces it. session info markup colors take the twelve names, not a hex.