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test could previously reach the real api.moonshot.cn), and the outdated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

@@ -129,9 +129,9 @@ pub enum TerminalName {
     /// indistinguishable. All capabilities are conservative/Unknown.
     #[strum(to_string = "JetBrains")]
     JetBrains,
-    /// Grok Desktop (Electron app).
-    #[strum(to_string = "Grok Desktop")]
-    GrokDesktop,
+    /// Kigi Desktop (Electron app).
+    #[strum(to_string = "Kigi Desktop")]
+    KigiDesktop,
     /// VTE-based terminal (GNOME Terminal, kgx/GNOME Console, Tilix, etc.).
     #[strum(to_string = "VTE")]
     Vte,
@@ -276,7 +276,7 @@ pub struct TerminalContext {
     pub multiplexer: MultiplexerKind,
     /// Whether Byobu is wrapping the session, and which backend it uses.
     pub byobu: Option<ByobuBackend>,
-    /// Which embedded editor `:terminal` grok is running inside, if any.
+    /// Which embedded editor `:terminal` kigi is running inside, if any.
     pub embedded_editor: Option<EmbeddedEditor>,
     /// tmux client metadata (populated only when `multiplexer == Tmux`).
     pub tmux_meta: TmuxClientMeta,
@@ -323,7 +323,7 @@ impl TerminalContext {
 
     /// Whether an outer layer (embedded-editor :terminal or multiplexer) can
     /// repaint our pane out of band, stranding rows until a full clear. A heal
-    /// keyed off this only fires when a FocusGained actually reaches grok, which
+    /// keyed off this only fires when a FocusGained actually reaches kigi, which
     /// needs focus reporting enabled upstream (e.g. tmux `focus-events on`, off
     /// by default).
     pub fn repaints_pane_out_of_band(&self) -> bool {
@@ -645,7 +645,7 @@ fn detect_terminal_context() -> TerminalContext {
     // per-pane vars don't survive) and over SSH (not forwarded), except
     // brands with SSH-surviving markers (the VS Code family, and iTerm2
     // via LC_TERMINAL). tmux -g global env is stale (reflects the server's
-    // first client, not the current one). Revisit when `grok ssh` can
+    // first client, not the current one). Revisit when `kigi ssh` can
     // forward env vars.
     let mut ctx = build_terminal_context_from_env(&env);
     ctx.brand = refine_unknown_brand_for_host(ctx.brand, HostOs::current());
@@ -980,7 +980,7 @@ fn terminal_name_from_term_program(value: &str) -> Option<TerminalName> {
         "rio" => Some(TerminalName::Rio),
         "terminator" => Some(TerminalName::Terminator),
         "zed" => Some(TerminalName::Zed),
-        "grokdesktop" => Some(TerminalName::GrokDesktop),
+        "kigidesktop" => Some(TerminalName::KigiDesktop),
         "windowsterminal" => Some(TerminalName::WindowsTerminal),
         "otty" => Some(TerminalName::Otty),
         _ => None,