§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test could previously reach the real api.moonshot.cn), and the outdated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/src/leader/protocol.rs

@@ -108,7 +108,7 @@ impl Default for ClientId {
 #[derive(Debug, Clone, Copy, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
 #[serde(rename_all = "snake_case")]
 pub enum ClientMode {
-    /// Stdio mode (grok agent stdio, grok -p) - uses local IPC.
+    /// Stdio mode (kigi agent stdio, kigi -p) - uses local IPC.
     /// Client sends/receives ACP messages directly via IPC.
     Stdio,
 }
@@ -143,7 +143,7 @@ pub struct ClientCapabilities {
     #[serde(default)]
     pub client_version: Option<String>,
 
-    /// Whether this client has advertised `x.ai/codeNavigation.enabled`.
+    /// Whether this client has advertised `kigi/codeNavigation.enabled`.
     /// When true, the leader injects `codeNavEnabled: true` into `session/new`
     /// and `session/load` requests so the agent can gate code-nav startup on a
     /// per-client basis rather than reading from shared last-initialized state.
@@ -177,7 +177,7 @@ pub struct LeaderCapabilities {
     pub profile_formats: Vec<ProfileArtifactFormat>,
     /// Whether the leader supports [`ControlCommand::RelaunchForUpdate`] — a
     /// disruptive, bounded-grace relaunch onto a freshly-installed binary
-    /// (driven by `grok update`). Old leaders default to `false`, so a new
+    /// (driven by `kigi update`). Old leaders default to `false`, so a new
     /// client falls back to advising a manual restart (graceful degradation).
     #[serde(default)]
     pub relaunch_v1: bool,
@@ -196,12 +196,12 @@ pub enum ControlCommand {
     },
     StopCpuProfile,
     /// Ask the leader to relaunch onto a freshly-installed binary (driven by
-    /// `grok update`). The leader stops admitting new turns, waits a bounded
+    /// `kigi update`). The leader stops admitting new turns, waits a bounded
     /// grace period for in-flight turns to finish, flushes session state, then
     /// exits with [`ShutdownReason::AutoUpdate`] so connected clients reconnect
     /// onto the new binary and restore their sessions via `session/load`.
     ///
-    /// `to_version` is the version `grok update` just installed; the leader uses
+    /// `to_version` is the version `kigi update` just installed; the leader uses
     /// it to decline if it is already running that version or newer.
     RelaunchForUpdate {
         to_version: String,