Fixed dark and light themes, ui.theme auto/dark/light

Colors no longer come from the terminal's palette, whose color 0 many
color themes set to a grey that is not their background. A theme sets
tview's default styles and the color names used in texts, all chosen from
entries 16-255 of the 256-color table so terminals without 24-bit color
show them exactly. "auto" picks light or dark from the background color
the terminal reports. Settable in the Config view, applied at the next
start (widgets copy their colors when created). Replaces using the
terminal's own background and text colors.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019reK4DUGYqDUjniWYJvwUW

internal/ui/probe_unix.go

@@ -14,7 +14,8 @@ import (
 
 // probeTerminal asks the terminal whether it understands the Kitty graphics
 // protocol (a tiny query image, which a capable terminal answers with "OK" and
-// does not show) and for its text and background colors (OSC 10 and 11). A Primary Device
+// does not show) and for its background color (OSC 11), which picks the
+// theme. A Primary Device
 // Attributes request follows, which every terminal answers, and answers come
 // in order: once the DA answer is in, whatever was not answered before it is
 // not supported. Runs before the screen is set up, on the controlling terminal.
@@ -31,7 +32,7 @@ func probeTerminal(timeout time.Duration) (info terminalInfo) {
 	}
 	defer term.Restore(fd, state)
 
-	const query = "\x1b_Gi=31,s=1,v=1,a=q,t=d,f=24;AAAA\x1b\\" + "\x1b]10;?\x1b\\" + "\x1b]11;?\x1b\\" + "\x1b[c"
+	const query = "\x1b_Gi=31,s=1,v=1,a=q,t=d,f=24;AAAA\x1b\\" + "\x1b]11;?\x1b\\" + "\x1b[c"
 	if _, err := tty.WriteString(query); err != nil {
 		return info
 	}