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test could previously reach the real api.moonshot.cn), and the outdated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

@@ -759,7 +759,7 @@ mod tests {
         let output = ToolOutput::Todo(TodoWriteOutput::TodosUpdated(TodoWriteSuccess {
             summary_for_prompt: "tasks".to_string(),
             todos: vec![],
-            state: kigi_tools::implementations::grok_build::todo::TodoState::default(),
+            state: kigi_tools::implementations::kigi::todo::TodoState::default(),
         }));
         let update = acp_tool_update(&output, "call-1", None, None).unwrap();
         assert_eq!(update.fields.status, Some(acp::ToolCallStatus::Completed));
@@ -768,7 +768,7 @@ mod tests {
     #[test]
     fn test_turn_end_plan_cleanup_preserves_semantics_and_priority() {
         use crate::tools::todo::plan_entry_from_todo_item;
-        use kigi_tools::implementations::grok_build::todo::{TodoItem, TodoPriority, TodoStatus};
+        use kigi_tools::implementations::kigi::todo::{TodoItem, TodoPriority, TodoStatus};
 
         // Simulate a mixed todo list at turn end.
         let items = [
@@ -836,13 +836,13 @@ mod tests {
     fn test_acp_plan_update_todo() {
         let output = ToolOutput::Todo(TodoWriteOutput::TodosUpdated(TodoWriteSuccess {
             summary_for_prompt: "tasks".to_string(),
-            todos: vec![kigi_tools::implementations::grok_build::todo::TodoItem {
+            todos: vec![kigi_tools::implementations::kigi::todo::TodoItem {
                 content: "Task 1".to_string(),
-                priority: kigi_tools::implementations::grok_build::todo::TodoPriority::Medium,
-                status: kigi_tools::implementations::grok_build::todo::TodoStatus::Completed,
+                priority: kigi_tools::implementations::kigi::todo::TodoPriority::Medium,
+                status: kigi_tools::implementations::kigi::todo::TodoStatus::Completed,
                 meta: None,
             }],
-            state: kigi_tools::implementations::grok_build::todo::TodoState::default(),
+            state: kigi_tools::implementations::kigi::todo::TodoState::default(),
         }));
         let plan = acp_plan_update(&output).unwrap();
         assert_eq!(plan.entries.len(), 1);