§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test could previously reach the real api.moonshot.cn), and the outdated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-shell/tests/test_summary_reasoning_effort.rs

@@ -5,7 +5,7 @@
 //! creation — not only after an explicit model/effort switch (the old
 //! behavior, which left the field absent for sessions that never switched).
 //!
-//! Each test spawns a real `grok agent stdio` process against a mock
+//! Each test spawns a real `kigi agent stdio` process against a mock
 //! inference server and asserts on the persisted `summary.json`.
 //!
 //! Run locally:
@@ -60,10 +60,10 @@ async fn test_fresh_session_persists_reasoning_effort() {
         // user config override (the same path a remote settings catalog entry or
         // `--effort` would populate).
         let home = tempfile::TempDir::new().expect("create temp home");
-        let grok_dir = home.path().join(".kigi");
-        std::fs::create_dir_all(&grok_dir).expect("create .kigi dir");
+        let kigi_dir = home.path().join(".kigi");
+        std::fs::create_dir_all(&kigi_dir).expect("create .kigi dir");
         std::fs::write(
-            grok_dir.join("config.toml"),
+            kigi_dir.join("config.toml"),
             r#"
 [model.test-model]
 supports_reasoning_effort = true
@@ -72,7 +72,7 @@ reasoning_effort = "high"
         )
         .expect("write config.toml");
 
-        let client = GrokStdioClient::spawn_with_home(&server, workdir.path(), home).await;
+        let client = KigiStdioClient::spawn_with_home(&server, workdir.path(), home).await;
         client.initialize_with_timeout().await;
         let session_id = client.create_session_with_timeout(workdir.path()).await;
         let result = client.prompt_with_timeout(&session_id, "say hello").await;
@@ -98,7 +98,7 @@ async fn test_fresh_session_without_effort_omits_field() {
             .await
             .expect("start mock server");
         let workdir = git_workdir();
-        let client = GrokStdioClient::spawn(&server, workdir.path()).await;
+        let client = KigiStdioClient::spawn(&server, workdir.path()).await;
 
         client.initialize_with_timeout().await;
         let session_id = client.create_session_with_timeout(workdir.path()).await;