§9 acceptance: grep-zero sweep — every internal x.ai/grok identifier renamed

The PRD's first acceptance gate now holds: grep -RinE '\bx\.ai\b|grok'
crates/ --include='*.rs' → 0 matches (exempt: NOTICE and third-party
license archives, README provenance, and the required 'Based on Grok
Build Open Source' attribution, now sourced from version_attribution.txt).

Wire-visible renames (both sides in this repo, changed in lockstep):
- Auth method id 'grok.com' → 'kimi-code' (AuthMethodKind::KimiCode).
- Every x.ai/* and _x.ai/* ACP ext method and meta key → kigi/* /
  _kigi/* (~200 names; grokShell → kigiShell). Session-file replay keeps
  a read-side alias for the legacy '_x.ai/session/update' method so
  existing updates.jsonl histories load; writes emit only the new name
  (both directions test-pinned).
- Agent types grok-build* → kigi* with a documented legacy-prefix alias
  at resolution time so persisted sessions keep resolving.
- ToolNamespace/BuiltinAgentName GrokBuild* → Kigi* (wire snake_case
  kigi/kigi_concise/kigi_hashline; schema regenerated); grok_build
  implementation dirs renamed to kigi*.
- x-grok-* headers → x-kigi-*, __GROK_* sentinels → __KIGI_*, themes
  grokday/groknight → kigiday/kiginight (old persisted values fall back
  to the default theme), web_fetch allowlist xAI hosts → kimi.com +
  moonshot platforms, changelog CDN → this repo, grok-build changelog
  archives deleted.
- BYOK default endpoint removed: [endpoints] api_base_url is now truly
  optional with NO default — consumers fail fast with the flag name when
  unset (no silent x.ai egress). Mock harnesses inject it explicitly.
- System-prompt identity fixed: 'released by xAI' → 'an unofficial
  community CLI for Kimi' (template + regenerated encrypted form).

Also repaired pre-existing grok-era test debt found by the sweep: the
stale trace_classify default-model pin, the grok-pager UA label test,
pty-harness stale-binary reuse and non-hermetic moonshot routing (a PTY
test could previously reach the real api.moonshot.cn), and the outdated
oauth fixture scope key.

Gates: §9 grep 0; fmt clean; workspace check/clippy 0/0 (-D warnings);
FULL cargo test --workspace: 234 suites, 21,961 passed, 0 failed;
deny advisories ok.

crates/codegen/kigi-tui/src/app/acp_handler/settings.rs

@@ -1,14 +1,14 @@
 use super::*;
 use serde::Deserialize;
 
-/// Handle `x.ai/models/update` — model list changed (etag-triggered refresh).
+/// Handle `kigi/models/update` — model list changed (etag-triggered refresh).
 pub(super) fn handle_models_update(notif: &acp::ExtNotification, app: &mut AppView) -> bool {
     if let Ok(model_state) = serde_json::from_str::<acp::SessionModelState>(notif.params.get()) {
         use crate::acp::model_state::ModelState;
         let new_models = ModelState::from(Some(model_state));
         tracing::info!(
             count = new_models.available.len(),
-            "models updated via x.ai/models/update"
+            "models updated via kigi/models/update"
         );
 
         let shell_fallback_current = new_models.current.clone();
@@ -46,15 +46,15 @@ pub(super) fn handle_models_update(notif: &acp::ExtNotification, app: &mut AppVi
         }
         true
     } else {
-        tracing::warn!("Failed to parse x.ai/models/update");
+        tracing::warn!("Failed to parse kigi/models/update");
         false
     }
 }
 
-/// Handle `x.ai/settings/update` — remote settings refreshed on `/new`.
+/// Handle `kigi/settings/update` — remote settings refreshed on `/new`.
 pub(super) fn handle_settings_update(notif: &acp::ExtNotification, app: &mut AppView) -> bool {
     let Ok(update) = serde_json::from_str::<PagerSettingsUpdate>(notif.params.get()) else {
-        tracing::warn!("Failed to parse x.ai/settings/update");
+        tracing::warn!("Failed to parse kigi/settings/update");
         return false;
     };
 
@@ -221,7 +221,7 @@ pub(super) fn handle_settings_update(notif: &acp::ExtNotification, app: &mut App
         }
     }
 
-    tracing::info!("settings updated via x.ai/settings/update");
+    tracing::info!("settings updated via kigi/settings/update");
     true
 }
 
@@ -249,7 +249,7 @@ pub(super) fn apply_soft_default_permission_mode(
 }
 
 /// Tell live sessions to leave Auto on the mid-session kill-switch: fire the
-/// `x.ai/yolo_mode_changed` notification the agent maps to
+/// `kigi/yolo_mode_changed` notification the agent maps to
 /// `SetAutoMode { enabled: false }`, fire-and-forget over the shared ACP channel.
 /// The notification is CLIENT-scoped (the agent applies it to every session of
 /// the sending client), so one send covers all affected sessions. `yolo_mode` is
@@ -264,7 +264,7 @@ pub(super) fn notify_sessions_leave_auto(app: &AppView, session_ids: &[acp::Sess
         "permission_mode": "ask",
     });
     let notification = acp::ExtNotification::new(
-        "x.ai/yolo_mode_changed",
+        "kigi/yolo_mode_changed",
         serde_json::value::to_raw_value(&params)
             .expect("serialize yolo_mode_changed params")
             .into(),
@@ -277,12 +277,12 @@ pub(super) fn notify_sessions_leave_auto(app: &AppView, session_ids: &[acp::Sess
     let _ = app.acp_tx.send(args.into());
 }
 
-/// Handle `x.ai/sessions/changed` — the leader broadcasts roster
+/// Handle `kigi/sessions/changed` — the leader broadcasts roster
 /// upserts/removals to all clients (FleetView dashboard).
 pub(super) fn handle_sessions_changed(notif: &acp::ExtNotification, app: &mut AppView) -> bool {
     let Ok(changed) = serde_json::from_str::<crate::app::roster::RosterChanged>(notif.params.get())
     else {
-        tracing::warn!("Failed to parse x.ai/sessions/changed");
+        tracing::warn!("Failed to parse kigi/sessions/changed");
         return false;
     };
     let mut affected = false;
@@ -297,7 +297,7 @@ pub(super) fn handle_sessions_changed(notif: &acp::ExtNotification, app: &mut Ap
     affected
 }
 
-/// Deserialization type for the `x.ai/settings/update` notification payload.
+/// Deserialization type for the `kigi/settings/update` notification payload.
 ///
 /// This is intentionally a separate struct from `SettingsUpdateNotification` in
 /// `kigi-shell/src/agent/mvp_agent.rs`. The shell side derives `Serialize`