§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test could previously reach the real api.moonshot.cn), and the outdated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-tui/src/views/queue_pane.rs

@@ -43,7 +43,7 @@ pub enum QueueRowOrigin {
     /// any idle-drained prompt). Edits mutate the local queue directly.
     Local,
     /// A server-authoritative `shared_prompt_queues` entry (plain prompt queued
-    /// while running). Edits route to the agent as `x.ai/queue/*`.
+    /// while running). Edits route to the agent as `kigi/queue/*`.
     Server,
 }
 
@@ -385,7 +385,7 @@ pub struct QueuePane {
     /// Theme kind at the last render. Used to detect a theme switch and
     /// refresh `list_style`, whose `selection_bg` is captured from the theme
     /// (otherwise the focused-row highlight keeps the previous theme's
-    /// `bg_highlight` — e.g. GrokNight's dark band leaking into GrokDay).
+    /// `bg_highlight` — e.g. KigiNight's dark band leaking into KigiDay).
     last_theme: ThemeKind,
     /// Shared visibility/focus state.
     pub overlay: OverlayState,
@@ -827,8 +827,8 @@ impl QueuePane {
         // Detect a theme switch and refresh the list chrome style. Its
         // `selection_bg` (the focused-row highlight) is captured from the
         // theme's `bg_highlight`; without this it would keep the theme active
-        // at construction (default GrokNight, dark) after the user switches —
-        // painting a dark band on a light GrokDay canvas.
+        // at construction (default KigiNight, dark) after the user switches —
+        // painting a dark band on a light KigiDay canvas.
         let current_theme = Theme::current_kind();
         if current_theme != self.last_theme {
             self.last_theme = current_theme;