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test could previously reach the real api.moonshot.cn), and the outdated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

@@ -5,7 +5,7 @@
     unreachable_code,
     dead_code
 )]
-//! OS-level sandboxing for Grok Build via [nono](https://crates.io/crates/nono).
+//! OS-level sandboxing for Kigi via [nono](https://crates.io/crates/nono).
 //!
 //! Applied once at process startup. Covers in-process `tokio::fs` calls
 //! and child processes. Network is left open at the process level (agent
@@ -48,7 +48,7 @@ static SANDBOX: OnceLock<GlobalSandboxState> = OnceLock::new();
 static CONFIGURED_PROFILE: OnceLock<String> = OnceLock::new();
 static RESTRICT_CHILD_NETWORK: AtomicBool = AtomicBool::new(false);
 static AUTO_ALLOW_BASH: AtomicBool = AtomicBool::new(false);
-const BWRAP_ENV_VAR: &str = "__GROK_INSIDE_BWRAP";
+const BWRAP_ENV_VAR: &str = "__KIGI_INSIDE_BWRAP";
 pub fn is_inside_bwrap() -> bool {
     std::env::var(BWRAP_ENV_VAR).is_ok()
 }
@@ -299,7 +299,7 @@ fn chmod_000(path: &Path) -> Option<()> {
 }
 /// Zero-permission placeholder (file or dir) under `kigi_home` used by bwrap bind-over.
 ///
-/// The placeholder name is suffixed with the current PID so concurrent grok
+/// The placeholder name is suffixed with the current PID so concurrent kigi
 /// processes don't race each other's create/remove/chmod on a shared path (which
 /// could yield `None` and the silent dropped-bind fail-open this avoids).
 #[cfg(all(feature = "enforce", target_os = "linux"))]
@@ -620,10 +620,10 @@ mod tests {
             .duration_since(std::time::UNIX_EPOCH)
             .unwrap()
             .as_nanos();
-        let ws = std::env::temp_dir().join(format!("grok-{tag}-{}-{nanos}", std::process::id()));
-        let grok = ws.join(".kigi");
-        std::fs::create_dir_all(&grok).unwrap();
-        std::fs::write(grok.join("sandbox.toml"), toml_body).unwrap();
+        let ws = std::env::temp_dir().join(format!("kigi-{tag}-{}-{nanos}", std::process::id()));
+        let kigi = ws.join(".kigi");
+        std::fs::create_dir_all(&kigi).unwrap();
+        std::fs::write(kigi.join("sandbox.toml"), toml_body).unwrap();
         ws
     }
     /// Create a temp workspace defining a `denytest` profile (extends `workspace`)
@@ -659,7 +659,7 @@ mod tests {
     #[cfg(all(feature = "enforce", target_os = "linux"))]
     fn bwrap_reexec_uses_dir_placeholder_for_directories() {
         let _g = EnvGuard::remove(BWRAP_ENV_VAR);
-        let dir = std::env::temp_dir().join(format!("grok-deny-dir-{}", std::process::id()));
+        let dir = std::env::temp_dir().join(format!("kigi-deny-dir-{}", std::process::id()));
         std::fs::create_dir_all(&dir).unwrap();
         let dir_str = dir.to_string_lossy().to_string();
         let result = bwrap_reexec_command(&[], &[&dir_str]);