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test could previously reach the real api.moonshot.cn), and the outdated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

@@ -1,4 +1,4 @@
-//! `grok mcp doctor` -- runtime health check for MCP servers.
+//! `kigi mcp doctor` -- runtime health check for MCP servers.
 
 use std::collections::HashMap;
 use std::path::Path;
@@ -510,13 +510,13 @@ pub async fn run_doctor(cwd: &Path, name_filter: Option<&str>) -> DoctorReport {
 
     let disabled_names = crate::util::config::disabled_mcp_server_names(cwd);
 
-    // Folder-trust gate: `grok mcp doctor` actually STARTS each server
+    // Folder-trust gate: `kigi mcp doctor` actually STARTS each server
     // (`check_server_start`), so in an untrusted clone it would spawn the repo's
     // project-scoped servers. Resolve the doctor cwd once (no prompt), then skip
     // (do not start) any project-scoped server when untrusted. Reuses the same
     // name primitive as the session/agent-pool gates.
     //
-    // `remote = None` is intentional: standalone `grok mcp doctor` has no loaded
+    // `remote = None` is intentional: standalone `kigi mcp doctor` has no loaded
     // `RemoteSettings`, so a remote-only org `folder_trust_enabled = false`
     // opt-out isn't seen here — gating conservatively (treating the feature as
     // enabled) is the deliberate fail-secure direction. Local env/user/managed
@@ -616,7 +616,7 @@ pub fn print_report(report: &DoctorReport) {
 
     if report.servers.is_empty() {
         println!("  No MCP servers configured.");
-        println!("  Run `grok mcp add --help` to get started.");
+        println!("  Run `kigi mcp add --help` to get started.");
         println!();
         return;
     }
@@ -646,7 +646,7 @@ pub fn print_report(report: &DoctorReport) {
         report.healthy_count,
         report.failing_count,
         if report.failing_count > 0 {
-            " Run `grok mcp doctor --json` for full diagnostics."
+            " Run `kigi mcp doctor --json` for full diagnostics."
         } else {
             ""
         }