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-pager-render/src/theme/mod.rs

@@ -139,12 +139,12 @@ pub fn canonical_name(value: &str) -> Option<&'static str> {
 }
 
 /// Human-friendly display name for a canonical theme value (e.g.
-/// `"groknight"` → `"Grok Night"`). Falls back to `value` verbatim.
+/// `"groknight"` → `"Kigi Night"`). Falls back to `value` verbatim.
 pub fn display_name_for_canonical(value: &str) -> &str {
     match value {
         "auto" => "Auto",
-        "groknight" => "Grok Night",
-        "grokday" => "Grok Day",
+        "groknight" => "Kigi Night",
+        "grokday" => "Kigi Day",
         "tokyonight" => "Tokyo Night",
         "rosepine-moon" => "Rose Pine Moon",
         other => other,