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test could previously reach the real api.moonshot.cn), and the outdated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

@@ -1,19 +1,19 @@
-//! Headless markdown analysis sharing Grok Build's exact `pulldown-cmark` config.
+//! Headless markdown analysis sharing Kigi's exact `pulldown-cmark` config.
 //!
 //! This crate is intentionally lean -- it depends only on `pulldown-cmark` -- so it
 //! can be used without pulling in the terminal-rendering stack (syntect, ratatui,
 //! two-face). [`parser_options`] is the single source of truth for the parser
-//! feature set, shared with `kigi-markdown` so analysis matches what Grok
+//! feature set, shared with `kigi-markdown` so analysis matches what Kigi
 //! Build actually renders 1:1.
 //!
-//! After parsing, Grok applies [`offset_events`]: only `~~…~~` is strikethrough.
+//! After parsing, Kigi applies [`offset_events`]: only `~~…~~` is strikethrough.
 //! Single-tilde pairs (`~text~`) are demoted to literal `~` text so LLM output
 //! like `~**10%**` is not struck (pulldown treats those pairs as strike; we do not).
 
 use pulldown_cmark::{CodeBlockKind, Event, HeadingLevel, Options, Parser, Tag, TagEnd};
 use std::ops::Range;
 
-/// The exact `pulldown-cmark` option set Grok Build uses to render markdown.
+/// The exact `pulldown-cmark` option set Kigi uses to render markdown.
 ///
 /// With `ENABLE_STRIKETHROUGH`, pulldown treats both `~~…~~` and single-`~` pairs as
 /// strike. Callers must consume events via [`offset_events`] so only double-tilde
@@ -26,7 +26,7 @@ pub fn parser_options() -> Options {
         | Options::ENABLE_TABLES
 }
 
-/// Offset event stream from Grok's parser, with single-tilde strikethrough demoted.
+/// Offset event stream from Kigi's parser, with single-tilde strikethrough demoted.
 ///
 /// Prefer this over `Parser::new_ext(...).into_offset_iter()` so analysis and
 /// rendering agree on what counts as strikethrough.
@@ -294,7 +294,7 @@ fn detect_malformed_tables(
     }
 }
 
-/// Parse `text` with Grok Build's options; count elements and flag structural issues.
+/// Parse `text` with Kigi's options; count elements and flag structural issues.
 pub fn analyze(text: &str) -> MarkdownAnalysis {
     let mut stats = MarkdownStats::default();
     let mut issues = Vec::new();