§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test could previously reach the real api.moonshot.cn), and the outdated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/scrollback/wrappers/entry_renderer.rs

@@ -407,7 +407,7 @@ impl<'a> EntryRenderer<'a> {
     ///
     /// Mirrors `desired_height` but derives the content line count from the block's
     /// raw source text (`searchable_text`) instead of laying it out. Lets the layout
-    /// cache size off-screen entries on a bulk load (`grok -r`) without word-wrapping
+    /// cache size off-screen entries on a bulk load (`kigi -r`) without word-wrapping
     /// and markdown-rendering every entry (O(history)). On-screen entries get their
     /// EXACT `desired_height`, so visible content is never estimated.
     pub fn estimate_height(&self, width: u16) -> u16 {
@@ -1486,7 +1486,7 @@ mod tests {
         // Background blocks own the gutter via the existing full-area fill, so
         // the no-bg clear must not run for them. Concrete theme so bg_light !=
         // bg_base (Theme::current() quantizes both to Reset in the test env).
-        let theme = Theme::groknight();
+        let theme = Theme::kiginight();
         assert_ne!(
             theme.bg_light, theme.bg_base,
             "test premise: block bg must differ from base bg"
@@ -1517,14 +1517,14 @@ mod tests {
         // code rectangle gets a notch. Concrete theme so the two bgs differ.
         //
         // Requires color support: under `NO_COLOR` the global markdown style
-        // carries no code background while this test's local `groknight()`
+        // carries no code background while this test's local `kiginight()`
         // theme still has RGB — a mismatch impossible in production.
         // (Historically this passed under NO_COLOR only because the md_style
         // Reset→silver fallback bug painted a concrete bg despite the opt-out.)
         if !crate::theme::color_support::detect().has_color() {
             return;
         }
-        let theme = Theme::groknight();
+        let theme = Theme::kiginight();
         let mut entry = ScrollbackEntry::new(RenderBlock::agent_message("```\nZZZZ\n```\n"));
         // The code block's only content row is the first content row, which is
         // also where the timestamp overlay lands. Drop `created_at` so the
@@ -1802,7 +1802,7 @@ mod tests {
 
         // The off-screen estimate accounts for the affordance row (one per
         // diagram) and so never under-reserves vs the realized height — the
-        // invariant a bulk load (`grok -r`) relies on to avoid clipping.
+        // invariant a bulk load (`kigi -r`) relies on to avoid clipping.
         let est_on = r.estimate_height(80);
         assert_eq!(
             est_on,
@@ -1872,7 +1872,7 @@ mod tests {
         // their previews as panel is pinned by block-side tests.)
         use crate::scrollback::block::StubBlock;
 
-        let theme = Theme::groknight();
+        let theme = Theme::kiginight();
         let entry = ScrollbackEntry::new(RenderBlock::Stub(
             StubBlock::new("alpha\nbravo", Color::Blue).with_line_bg(LINE_BG, true),
         ));
@@ -1900,7 +1900,7 @@ mod tests {
         // tool-preview panels.
         use crate::scrollback::block::StubBlock;
 
-        let theme = Theme::groknight();
+        let theme = Theme::kiginight();
         let entry = ScrollbackEntry::new(RenderBlock::Stub(
             StubBlock::new("alpha\nbravo", Color::Blue).with_line_bg(LINE_BG, false),
         ));