§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test could previously reach the real api.moonshot.cn), and the outdated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-shell/src/session/commands.rs

@@ -186,10 +186,10 @@ pub enum SessionCommand {
     /// and does NOT update `primaryModelId` in signals — the resolved model
     /// is already tracked via inference responses), this command also calls
     /// `set_primary_model()` so that signals report the override model
-    /// rather than the agent-level default (e.g. `grok-4.5`).
+    /// rather than the agent-level default (e.g. `kigi-4.5`).
     ///
     /// Keeps the existing base_url, api_key, and other config — only changes
-    /// the `model` field sent in the `x-grok-model-override` header and merges
+    /// the `model` field sent in the `x-kigi-model-override` header and merges
     /// any additional headers (e.g. `x-openrouter-api-key` for BYOK).
     ///
     /// Used to set model IDs (e.g. opaque third-party routing names) that are
@@ -256,7 +256,7 @@ pub enum SessionCommand {
         request: RewindRequest,
         respond_to: oneshot::Sender<anyhow::Result<RewindResponse>>,
     },
-    /// Out-of-band history repair (`x.ai/session/repair`): fix tool-pairing
+    /// Out-of-band history repair (`kigi/session/repair`): fix tool-pairing
     /// violations (orphaned/displaced `ToolResult`s, duplicates, unanswered
     /// calls) that would otherwise 400 on every request. `dry_run` only
     /// reports. Refused while a turn is in flight.
@@ -329,7 +329,7 @@ pub enum SessionCommand {
         respond_to: oneshot::Sender<()>,
     },
     /// Update MCP servers for an existing session (used during reconnect or
-    /// mid-session via the `x.ai/session/update_mcp_servers` extension method).
+    /// mid-session via the `kigi/session/update_mcp_servers` extension method).
     /// This replaces the current MCP server configuration and triggers re-initialization.
     ///
     /// The caller is notified via `respond_to` once MCP re-initialization
@@ -453,7 +453,7 @@ pub enum SessionCommand {
         action: kigi_hooks_plugins_types::PluginsAction,
         respond_to: oneshot::Sender<kigi_hooks_plugins_types::ActionOutcome>,
     },
-    /// This session's plugin registry, as served by `x.ai/plugins/list`.
+    /// This session's plugin registry, as served by `kigi/plugins/list`.
     PluginsList {
         respond_to: oneshot::Sender<Option<std::sync::Arc<kigi_agent::plugins::PluginRegistry>>>,
     },
@@ -515,7 +515,7 @@ pub enum SessionCommand {
     },
     /// Replace the text of a queued (not-yet-running) prompt in place
     /// (server-side LWW). Last write wins via the actor's
-    /// serialized mailbox; the rebroadcast of `x.ai/queue/changed` is the
+    /// serialized mailbox; the rebroadcast of `kigi/queue/changed` is the
     /// truth signal for every attached client. The original `owner`
     /// attribution is preserved; `editor` is recorded as the most recent
     /// editor (for future "alice edited this" UX). A missing id, or an id
@@ -533,7 +533,7 @@ pub enum SessionCommand {
     /// like [`RemoveQueuedPrompt`]. A benign no-op (the prompt stays queued and
     /// runs normally) when no turn is running, the id names the running turn, is
     /// stale/already-drained, or `owner` doesn't match. The rebroadcast of
-    /// `x.ai/queue/changed` is the truth signal for every attached client.
+    /// `kigi/queue/changed` is the truth signal for every attached client.
     InterjectQueuedPrompt {
         id: String,
         expected_version: u64,
@@ -630,7 +630,7 @@ pub enum SessionCommand {
     ///
     /// Fired by the client after a turn completes. The session builds a
     /// compact text-only transcript of the recent conversation, makes one
-    /// tool-free model call (default `grok-build-0.1` when available via
+    /// tool-free model call (default `kigi-0.1` when available via
     /// `model_override`, else the session model), sanitizes the output, and
     /// returns the predicted prompt via `respond_to`. Best-effort: any
     /// failure returns `None`.
@@ -640,7 +640,7 @@ pub enum SessionCommand {
     },
     /// Rewrite a raw memory note into well-structured markdown via a one-shot
     /// LLM call. The session uses `prepare_chat_completion()` with
-    /// `grok-build` model, low temperature, and capped output tokens.
+    /// `kigi` model, low temperature, and capped output tokens.
     RewriteMemoryNote {
         raw_text: String,
         context_summary: String,
@@ -653,7 +653,7 @@ pub enum SessionCommand {
     Interject {
         text: String,
         /// Client-minted id echoed back on the broadcast
-        /// `x.ai/session/interjection` so the originating pager can dedup its
+        /// `kigi/session/interjection` so the originating pager can dedup its
         /// optimistic local block. `None` from older clients.
         id: Option<String>,
         /// Pasted images riding along with the interjection. Empty from