§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test could previously reach the real api.moonshot.cn), and the outdated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/skills/create-skill/SKILL.md

@@ -1,15 +1,15 @@
 ---
 name: create-skill
 description: >
-  Interactively create a new Grok skill (SKILL.md + optional scripts/references).
+  Interactively create a new Kigi skill (SKILL.md + optional scripts/references).
   Use when the user wants to create a skill, scaffold a skill, or runs /create-skill.
 metadata:
-  short-description: "Create a new Grok skill"
+  short-description: "Create a new Kigi skill"
 ---
 
 # Create Skill
 
-Interactively gather requirements from the user and create a fully working Grok skill on disk.
+Interactively gather requirements from the user and create a fully working Kigi skill on disk.
 
 ## Step 1: Gather information
 
@@ -26,7 +26,7 @@ Ask the user the following questions **one at a time as regular conversation que
 
 Write a `description` frontmatter value that includes:
 - What the skill does (1-2 sentences)
-- Trigger phrases and keywords so Grok knows when to auto-invoke it
+- Trigger phrases and keywords so Kigi knows when to auto-invoke it
 - The slash command name (e.g. "Use when the user runs /deploy-k8s")
 
 Show the drafted description to the user and let them approve or edit it.
@@ -69,7 +69,7 @@ Also write any supporting files (scripts, references) using the same create meth
 2. Tell the user the skill is ready and how to use it:
    - Slash command: `/<skill-name>`
    - TUI menu: `/skills <skill-name>`
-   - Automatic: Grok will invoke it when the description matches user intent
+   - Automatic: Kigi will invoke it when the description matches user intent
 3. Tell the user the skill should appear in the slash menu within a few seconds (skills auto-reload when files change on disk).
 
 ## Guidelines

crates/codegen/kigi-shell/skills/help/SKILL.md

@@ -1,17 +1,17 @@
 ---
 name: help
 description: >
-  Grok documentation and configuration help. Use when users ask about
+  Kigi documentation and configuration help. Use when users ask about
   setup, configuration, MCP servers, authentication, skills, slash commands,
-  keyboard shortcuts, or any Grok feature. Also use proactively when you
+  keyboard shortcuts, or any Kigi feature. Also use proactively when you
   detect a user is having trouble with setup or onboarding.
 metadata:
-  short-description: "Grok docs — config, MCP, auth, skills, commands"
+  short-description: "Kigi docs — config, MCP, auth, skills, commands"
 ---
 
-# Grok Help
+# Kigi Help
 
-Answer the user's question about Grok setup, configuration, or features.
+Answer the user's question about Kigi setup, configuration, or features.
 
 ## Steps