§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test could previously reach the real api.moonshot.cn), and the outdated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/dispatch/tests/mod.rs

@@ -116,8 +116,8 @@ fn test_app() -> AppView {
         agent_override: None,
         bootstrap_acp_commands: Vec::new(),
         auth_methods: vec![acp::AuthMethod::Agent(acp::AuthMethodAgent::new(
-            acp::AuthMethodId::new("grok.com"),
-            "Grok".to_string(),
+            acp::AuthMethodId::new("kimi-code"),
+            "Kigi".to_string(),
         ))],
         auth_state: AuthState::Done,
         trust_state: TrustState::Done,
@@ -462,7 +462,7 @@ fn fork_test_app() -> AppView {
     app
 }
 /// Build a minimal `AcpArgs<acp::ExtRequest>` for an
-/// `x.ai/ask_user_question` ext-method request. Returns the args
+/// `kigi/ask_user_question` ext-method request. Returns the args
 /// plus the receiver half of the response oneshot so the test can
 /// assert the handler completes the ACP roundtrip.
 fn make_ask_user_question_args(
@@ -471,14 +471,13 @@ fn make_ask_user_question_args(
     kigi_acp_lib::AcpArgs<acp::ExtRequest>,
     tokio::sync::oneshot::Receiver<kigi_acp_lib::AcpResult<acp::ExtResponse>>,
 ) {
-    use kigi_tools::implementations::grok_build::ask_user_question::{
+    use kigi_tools::implementations::kigi::ask_user_question::{
         AskUserQuestionExtRequest, Question, QuestionOption,
     };
     let req = AskUserQuestionExtRequest {
         session_id: "test-session".into(),
         tool_call_id: tool_call_id.into(),
-        mode:
-            kigi_tools::implementations::grok_build::ask_user_question::AskUserQuestionMode::Default,
+        mode: kigi_tools::implementations::kigi::ask_user_question::AskUserQuestionMode::Default,
         questions: vec![Question {
             question: "ACP-driven question".into(),
             options: vec![QuestionOption {
@@ -493,7 +492,7 @@ fn make_ask_user_question_args(
     };
     let (tx, rx) = tokio::sync::oneshot::channel();
     let ext = acp::ExtRequest::new(
-        "x.ai/ask_user_question",
+        "kigi/ask_user_question",
         serde_json::value::to_raw_value(&req)
             .expect("serialize AskUserQuestionExtRequest")
             .into(),
@@ -742,7 +741,7 @@ fn with_theme_test_env(f: impl FnOnce()) {
         .unwrap_or_else(|e| e.into_inner());
     crate::theme::cache::reset_for_test();
     crate::theme::cache::seed_auto_theme_defaults_for_test();
-    crate::theme::cache::set(crate::theme::ThemeKind::GrokNight);
+    crate::theme::cache::set(crate::theme::ThemeKind::KigiNight);
     crate::theme::system_appearance::clear_mock();
     f();
     crate::theme::system_appearance::clear_mock();