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test could previously reach the real api.moonshot.cn), and the outdated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

@@ -19,7 +19,7 @@ pub fn tool_identity_of(metadata: &dyn ToolMetadata) -> ToolIdentity {
         read_only: metadata.is_read_only(),
     }
 }
-/// Resolve `wire_name` in `toolset` and merge the canonical `x.ai/tool` object
+/// Resolve `wire_name` in `toolset` and merge the canonical `kigi/tool` object
 /// into `existing` (see [`CanonicalToolMeta::merge_into`]). Returns `existing`
 /// unchanged when the tool is unknown (uninitialized MCP, backend-hosted), so
 /// markers like `bash_mode`/`backend` are never clobbered. This is the harness
@@ -51,7 +51,7 @@ pub fn norm_offset_i64(offset: Option<i64>) -> Option<u64> {
     }
 }
 /// Project a tool's **typed** input into the harness-independent `input` dict of
-/// the `x.ai/tool` `_meta` object. Equivalent tools across toolsets emit the
+/// the `kigi/tool` `_meta` object. Equivalent tools across toolsets emit the
 /// same keys with the same meaning (a harness may add an extra key).
 ///
 /// Returns `None` for tools with no stable cross-harness shape (MCP / dynamic /
@@ -135,8 +135,8 @@ mod tests {
     }
     #[test]
     fn canonical_omits_absent_options_not_null() {
-        let grok = parse(serde_json::json!({ "variant" : "ReadFile", "target_file" : "/a" }));
-        let g = canonical_input(&grok).unwrap();
+        let kigi = parse(serde_json::json!({ "variant" : "ReadFile", "target_file" : "/a" }));
+        let g = canonical_input(&kigi).unwrap();
         let keys: Vec<&String> = g.as_object().unwrap().keys().collect();
         assert_eq!(
             keys,