§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test could previously reach the real api.moonshot.cn), and the outdated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-pager-render/src/terminal/image.rs

@@ -54,7 +54,7 @@ static GRAPHICS_PROTOCOL: OnceLock<GraphicsProtocol> = OnceLock::new();
 
 /// When set, scrollback inline-media overlays are forced **off** process-wide,
 /// regardless of the terminal's graphics capability. The scrollback-native
-/// minimal mode (`grok --minimal`) sets this once at startup: it never runs the
+/// minimal mode (`kigi --minimal`) sets this once at startup: it never runs the
 /// interactive draw loop that paints inline images, so committed media blocks
 /// must always fall back to the `[Open …]` text affordance — and must not
 /// reserve blank image rows. See [`set_inline_overlay_force_off`].
@@ -281,8 +281,8 @@ fn convert_via_sips(image_data: &[u8]) -> Option<Vec<u8>> {
         .duration_since(std::time::UNIX_EPOCH)
         .unwrap_or_default()
         .as_nanos();
-    let src = tmp_dir.join(format!("grok-sips-{id}-{ts}.dat"));
-    let dst = tmp_dir.join(format!("grok-sips-{id}-{ts}.png"));
+    let src = tmp_dir.join(format!("kigi-sips-{id}-{ts}.dat"));
+    let dst = tmp_dir.join(format!("kigi-sips-{id}-{ts}.png"));
 
     // Write source bytes to temp file.
     let mut f = std::fs::File::create(&src).ok()?;