F3: Kimi inference pipeline + full grok cloud-surface excision

Sampler / inference (PRD F3):
- kimi_compat.rs: single adaptation point for the Kimi chat/completions
  dialect (thinking-field mapping, model_id stripping, empty-content
  tool-call message fix, stream_options.include_usage), with kimi-cli
  source citations
- Rate-limit handling reworked for Kimi/Moonshot semantics; UA kigi/{version}
- /models replaces the xAI models-v2 endpoint everywhere; idle model
  refresh carries X-Msh-* device headers only (X-XAI-Token-Auth and
  x-grok-client-mode/CLIENT_MODE_HEADER machinery deleted)

Cloud-surface excision (PRD §5, zero-egress):
- remote/ conversations lane, cli-chat-proxy-types crate, prod/ dir,
  share command, credit bar: deleted (single local session lane;
  paginate() replaces merge_and_paginate)
- Subscription/tier gate stack deleted end-to-end: AppView
  gate/tier/team/ZDR fields, app/subscription.rs watch loop,
  dispatch/billing.rs paywall + SuperGrok upsell, free-usage-exhausted
  chain, tier-restricted commands, GateInfo, RemoteSettings gate fields,
  SettingsUpdateNotification gate fields
- /privacy + coding-data-sharing setting deleted (backed by a dead xAI
  RPC; Kigi is zero-egress — nothing to share or retain remotely)

Auth UX correctness (user-reported):
- Device-flow fixtures now mirror the live Kimi payload shape
  (https://www.kimi.com/code/authorize_device?user_code=..., verified
  against auth.kimi.com); the fabricated auth.kimi.com/device?code=...
  URLs are gone
- open_browser_detached is a no-op under cfg(test): unit tests drove
  wiremock fixture URLs into the real browser (root cause of the
  "garbage mock link" ABCD-1234 tabs)
- Welcome/pager-minimal rebrand: Grok Build -> Kigi, grok.com ->
  kimi.com, "Sign in to Grok" -> "Sign in to Kimi"

crates/codegen/kigi-tui/src/app/cli.rs

@@ -38,9 +38,6 @@ pub enum Command {
         #[arg(long)]
         json: bool,
     },
-    /// Share a session and print the share URL
-    #[command(hide = true)]
-    Share(crate::share_cmd::ShareArgs),
     /// Run any command with local clipboard support (OSC 52 → system clipboard).
     #[cfg_attr(not(any(unix, windows)), command(hide = true))]
     #[command(long_about = "\
@@ -268,8 +265,8 @@ pub struct AgentArgs {
     #[arg(long, conflicts_with = "leader")]
     pub no_leader: bool,
     /// Override the CLI chat proxy base URL.
-    #[arg(long = "cli-chat-proxy-base-url")]
-    pub cli_chat_proxy_base_url: Option<String>,
+    #[arg(long = "coding-api-base-url")]
+    pub coding_api_base_url: Option<String>,
     /// Override the public xAI API base URL.
     #[arg(long = "xai-api-base-url")]
     pub xai_api_base_url: Option<String>,