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test could previously reach the real api.moonshot.cn), and the outdated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

@@ -72,7 +72,7 @@ struct ReinitOutcome {
 struct AgentLoadOutcome {
     agent_id: super::agent::AgentId,
     success: bool,
-    /// `x.ai/runningPromptId` from the reload response: the turn another
+    /// `kigi/runningPromptId` from the reload response: the turn another
     /// client is driving mid-reconnect, adopted at finalize (mirrors the
     /// `SessionLoaded` adoption in `dispatch.rs`).
     running_prompt_id: Option<String>,
@@ -635,12 +635,12 @@ pub(crate) async fn run(
                 crate::acp::AuthStartMode::Command => super::app_view::AuthMode::Command,
             };
         } else {
-            // --force-login: find the grok.com method from the advertised list
-            let grok_com = connection
+            // --force-login: find the kimi.com method from the advertised list
+            let kigi_com = connection
                 .auth_methods
                 .iter()
-                .find(|m| m.id().0.as_ref() == "grok.com");
-            if let Some(method) = grok_com {
+                .find(|m| m.id().0.as_ref() == "kimi-code");
+            if let Some(method) = kigi_com {
                 app.login_label = Some(method.name().to_string());
                 app.login_method_id = Some(method.id().clone());
                 let is_provider = method
@@ -655,7 +655,7 @@ pub(crate) async fn run(
                     super::app_view::AuthMode::Pending
                 };
             } else {
-                // No grok.com method available, use the first method as fallback
+                // No kimi.com method available, use the first method as fallback
                 let first = &connection.auth_methods[0];
                 app.login_label = Some(first.name().to_string());
                 app.login_method_id = Some(first.id().clone());
@@ -667,7 +667,7 @@ pub(crate) async fn run(
         // by reusing dispatch_login. Effects are stashed and drained after
         // the initial render so the user sees the auth UI right away.
         // Empty auth_methods (preferred_method pin with no credentials) is
-        // fail-closed: do not invent grok.com / auto-start OIDC.
+        // fail-closed: do not invent kimi.com / auto-start OIDC.
         tracing::info!(
             method_id = ?app.login_method_id,
             methods_empty = connection.auth_methods.is_empty(),
@@ -1243,7 +1243,7 @@ pub(crate) async fn run(
         }
     }
 
-    // `grok dashboard` startup: open the dashboard view immediately. The
+    // `kigi dashboard` startup: open the dashboard view immediately. The
     // CLI subcommand wrote a `KIGI_OPEN_DASHBOARD_AT_STARTUP=1` env var
     // so we don't have to thread a flag through every arg struct.
     if std::env::var("KIGI_OPEN_DASHBOARD_AT_STARTUP").as_deref() == Ok("1") {