Rebrand remaining user-visible Grok strings to Kigi/Kimi

The welcome hero subtitle still read "Thanks for trying Grok Build";
theme display names, the NO_COLOR/COLORTERM diagnostics notes, the
permission notification title, the self-update restart hints, and the
clipboard-wrap protocol marker all still said Grok. Canonical theme keys
(groknight/grokday) are unchanged — only display strings move.

crates/codegen/kigi-tui/src/app/agent_view/interactions.rs

@@ -1619,8 +1619,8 @@ mod question_no_freeform_tests {
         Question {
             question: "You hit your free usage limit.".into(),
             options: vec![
-                opt("Upgrade to SuperGrok", "For everyday coding"),
-                opt("Upgrade to SuperGrok Heavy", "Highest usage limits"),
+                opt("Option A", "For everyday coding"),
+                opt("Option B", "Highest usage limits"),
             ],
             multi_select: Some(false),
             id: None,