§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test could previously reach the real api.moonshot.cn), and the outdated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-test-support/src/acp_client.rs

@@ -1,5 +1,5 @@
-//! ACP stdio clients for testing grok sessions end-to-end: the typed
-//! [`GrokStdioClient`] (`agent-client-protocol::ClientSideConnection` —
+//! ACP stdio clients for testing kigi sessions end-to-end: the typed
+//! [`KigiStdioClient`] (`agent-client-protocol::ClientSideConnection` —
 //! authentication, session lifecycle, permissions, notification streaming) and
 //! the raw-wire [`RawStdioClient`] (verbatim JSON-RPC lines for shapes the
 //! typed client can't produce), plus the shared subprocess spawn/stderr-capture
@@ -15,14 +15,14 @@ use kigi_acp_lib::LineBufferedRead;
 use tempfile::TempDir;
 use tokio_util::compat::{TokioAsyncReadCompatExt, TokioAsyncWriteCompatExt};
 
-use crate::env::{grok_binary, test_env_cmd_tokio};
+use crate::env::{kigi_binary, test_env_cmd_tokio};
 use crate::headless::stderr_tail;
 use crate::mock_server::MockInferenceServer;
 use crate::process::spawn_piped_with_stderr_capture;
 
-/// Spawn `grok agent stdio` with the canonical hermetic test env: the sandbox
+/// Spawn `kigi agent stdio` with the canonical hermetic test env: the sandbox
 /// from [`test_env_cmd_tokio`] plus the debug-logging kill-list, so the
-/// hermeticity setup exists exactly once for the typed ([`GrokStdioClient`])
+/// hermeticity setup exists exactly once for the typed ([`KigiStdioClient`])
 /// and raw ([`RawStdioClient`]) harnesses. `leading_args` go before the
 /// `agent stdio` subcommand (global flags); `extra_env` is applied after the
 /// kill-list so a test can still set e.g. `KIGI_DEBUG_LOG=1` explicitly.
@@ -33,7 +33,7 @@ fn spawn_agent_process(
     extra_env: &[(&str, &str)],
     leading_args: &[&str],
 ) -> (tokio::process::Child, Arc<std::sync::Mutex<Vec<u8>>>) {
-    let binary = grok_binary();
+    let binary = kigi_binary();
 
     let mut cmd = tokio::process::Command::new(&binary);
     cmd.args(leading_args)
@@ -107,11 +107,11 @@ impl acp::Client for TestAcpClient {
     }
 }
 
-/// Drives `grok agent stdio` via the ACP protocol over pipes.
+/// Drives `kigi agent stdio` via the ACP protocol over pipes.
 ///
 /// Handles the full lifecycle: spawn → initialize → authenticate → session → prompt.
 /// Child process is killed on drop.
-pub struct GrokStdioClient {
+pub struct KigiStdioClient {
     conn: acp::ClientSideConnection,
     _child: tokio::process::Child,
     home: Option<TempDir>,
@@ -119,7 +119,7 @@ pub struct GrokStdioClient {
     stderr: Arc<std::sync::Mutex<Vec<u8>>>,
 }
 
-impl GrokStdioClient {
+impl KigiStdioClient {
     pub async fn spawn(server: &MockInferenceServer, cwd: &Path) -> Self {
         let home = TempDir::new().expect("create temp home");
         Self::spawn_with_home(server, cwd, home).await
@@ -396,9 +396,9 @@ impl GrokStdioClient {
     }
 }
 
-/// Drives `grok agent stdio` with verbatim newline-delimited JSON-RPC lines.
+/// Drives `kigi agent stdio` with verbatim newline-delimited JSON-RPC lines.
 ///
-/// Exists for wire shapes the typed [`GrokStdioClient`] (`ClientSideConnection`,
+/// Exists for wire shapes the typed [`KigiStdioClient`] (`ClientSideConnection`,
 /// integer ids) can never produce — e.g. Xcode's Swift/Foundation `JSONEncoder`
 /// output: escaped-slash methods (`"session\/prompt"`) and string UUID request
 /// ids. Child process is killed on drop.