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/modals.rs

@@ -635,8 +635,7 @@ impl AgentView {
                 entries: _, state, ..
             } => {
                 // Build filtered entries for count and non-selectable indices.
-                let filtered =
-                    crate::views::modal::filter_palette_entries(&state.query, self.sharing_enabled);
+                let filtered = crate::views::modal::filter_palette_entries(&state.query);
                 let non_sel: Vec<bool> = filtered
                     .iter()
                     .map(|e| matches!(e.command, PaletteCommand::SectionHeader(_)))
@@ -840,14 +839,10 @@ impl AgentView {
                     }
                     PickerOutcome::Changed => {
                         // Re-filter entries based on updated query.
-                        let sharing_enabled = self.sharing_enabled;
                         if let Some(ActiveModal::CommandPalette { entries, state, .. }) =
                             self.active_modal.as_mut()
                         {
-                            *entries = crate::views::modal::filter_palette_entries(
-                                &state.query,
-                                sharing_enabled,
-                            );
+                            *entries = crate::views::modal::filter_palette_entries(&state.query);
                             state.selected = state.selected.min(entries.len().saturating_sub(1));
                         }
                         InputOutcome::Changed
@@ -1623,7 +1618,7 @@ impl AgentView {
             } = active_modal
             {
                 // Command palette: ModalWindow chrome + picker content.
-                let filtered = modal::filter_palette_entries(&state.query, self.sharing_enabled);
+                let filtered = modal::filter_palette_entries(&state.query);
                 let non_sel: Vec<bool> = filtered
                     .iter()
                     .map(|e| matches!(e.command, modal::PaletteCommand::SectionHeader(_)))
@@ -2614,7 +2609,7 @@ mod command_palette_vim_input_tests {
     // INPUT mode (`input_active`) over the full palette entries.
     fn open_command_palette(agent: &mut AgentView) {
         agent.active_modal = Some(ActiveModal::CommandPalette {
-            entries: crate::views::modal::default_palette_entries(agent.sharing_enabled),
+            entries: crate::views::modal::default_palette_entries(),
             state: PickerState::input_active(),
             window: crate::views::modal_window::ModalWindowState::new(),
         });