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/dispatch/tests/mod.rs

@@ -15,10 +15,6 @@ mod status;
 mod task_result;
 mod transcript;
 mod turn;
-use super::billing::{
-    CreditLimitUpsellMode, credit_limit_upsell_mode, is_max_tier, open_credit_limit_upsell,
-    open_free_usage_upsell,
-};
 use super::ctx::{find_agent_by_session_id, get_active_agent, get_active_agent_mut};
 use super::dashboard::{
     apply_pending_dispatch_config, dispatch_dashboard_attach, dispatch_dashboard_begin_rename,
@@ -133,24 +129,9 @@ fn test_app() -> AppView {
         deferred_startup: Default::default(),
         auth_use_oauth: false,
         auth_clipboard_copied: false,
-        team_id: None,
-        team_name: None,
-        is_zdr: false,
-        team_role: None,
-        coding_data_retention_opt_out: false,
         show_tips: None,
         auto_update: None,
         ask_user_question_timeout_enabled: None,
-        zdr_access_enabled: false,
-        usage_billing_redirect_url: None,
-        access_gate_shown_logged: false,
-        gate: None,
-        subscription_tier: None,
-        paywall_check_started: None,
-        last_subscription_check_at: None,
-        subscription_watch_interval_secs: None,
-        pending_gate_verification: None,
-        gate_verify_gen: 0,
         bundle_state: crate::app::bundle::BundleState::default(),
         scroll_debug_hud: crate::views::scroll_debug_hud::ScrollDebugHud::new(),
         fps_hud: crate::views::fps_hud::FpsHud::new(),
@@ -172,8 +153,6 @@ fn test_app() -> AppView {
         welcome_on_auth_url: false,
         welcome_on_changelog_cta: false,
         welcome_auth_fallback_rect: None,
-        welcome_refresh_rect: None,
-        welcome_gate_url_rect: None,
         welcome_changelog_cta_rect: None,
         auth_show_raw_url: false,
         auth_mouse_disabled: false,
@@ -213,13 +192,8 @@ fn test_app() -> AppView {
         minimal_state: crate::minimal_api::MinimalState::default(),
         reconnect_pending: false,
         show_resolved_model: true,
-        sharing_enabled: false,
         usage_visible: true,
-        tier_restricted_commands: Vec::new(),
         leader_mode: true,
-        credit_balance: None,
-        auto_topup: None,
-        billing_poll_wanted: false,
         leader_roster: Vec::new(),
         dashboard_local_sessions: Vec::new(),
         dashboard_sessions_loading: false,
@@ -262,8 +236,6 @@ fn make_test_agent_session(app: &AppView, id: AgentId, sid: &str) -> AgentSessio
         restore_degree: None,
         rate_limited: false,
         model_incompatible: false,
-        credit_limit_blocked: false,
-        free_usage_blocked: false,
         available_commands: Vec::new(),
         available_commands_generation: 0,
         available_tools: None,
@@ -446,8 +418,6 @@ fn insert_placeholder_agent(app: &mut AppView, id: AgentId) {
             restore_degree: None,
             rate_limited: false,
             model_incompatible: false,
-            credit_limit_blocked: false,
-            free_usage_blocked: false,
             available_commands: Vec::new(),
             available_commands_generation: 0,
             available_tools: None,
@@ -591,8 +561,6 @@ fn two_agent_app_with_bg_task() -> AppView {
             restore_degree: None,
             rate_limited: false,
             model_incompatible: false,
-            credit_limit_blocked: false,
-            free_usage_blocked: false,
             available_commands: Vec::new(),
             available_commands_generation: 0,
             available_tools: None,
@@ -895,17 +863,3 @@ fn reset_mouse_capture_enabled(on: bool) {
 fn mouse_capture_is_enabled() -> bool {
     crate::app::MOUSE_CAPTURE_ENABLED.load(std::sync::atomic::Ordering::Acquire)
 }
-/// Build a minimal `CreditBalance` for billing dispatch tests.
-fn test_bal(usage_pct: f64) -> crate::views::credit_bar::CreditBalance {
-    crate::views::credit_bar::CreditBalance {
-        usage_pct,
-        effective_usage_pct: usage_pct,
-        period_end_display: None,
-        pay_as_you_go: false,
-        on_demand_cap_cents: None,
-        on_demand_used_cents: None,
-        prepaid_balance_cents: None,
-        period_type: None,
-        is_unified_billing_user: None,
-    }
-}