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/views/dashboard/peek.rs

@@ -520,8 +520,6 @@ fn paint_peek_config_badge(
         model_name: &model_label,
         flags: &flags,
         multiline,
-        usage_warning: None,
-        usage_warning_critical: false,
     };
     // Bottom border row, inside the corners — the same content rect the
     // chat prompt and dispatch box use for their info line.
@@ -1111,7 +1109,6 @@ pub fn extract_last_response_type(agent: &AgentView) -> String {
             RenderBlock::BgTask(_) => return "Task".to_string(),
             RenderBlock::Btw(_) => return "Btw".to_string(),
             RenderBlock::ContextInfo(_) => return "Context".to_string(),
-            RenderBlock::CreditLimit(_) => return "Credit limit".to_string(),
             // The user's latest input marks the turn boundary — there's
             // no agent response after it yet.
             RenderBlock::UserPrompt(_) => break,
@@ -1310,7 +1307,6 @@ fn block_short_text(block: &crate::scrollback::block::RenderBlock) -> Option<Str
         RenderBlock::Subagent(_) => Some("(subagent)".to_string()),
         RenderBlock::Btw(_) => Some("(btw)".to_string()),
         RenderBlock::ContextInfo(_) => Some("(context info)".to_string()),
-        RenderBlock::CreditLimit(_) => Some("(credit limit)".to_string()),
         RenderBlock::Stub(_) => None,
     }
 }

crates/codegen/kigi-tui/src/views/dashboard/render.rs

@@ -2596,8 +2596,6 @@ fn paint_dispatch_config_badge(
         model_name: &model_label,
         flags: &flags,
         multiline: state.multiline_mode,
-        usage_warning: None,
-        usage_warning_critical: false,
     };
     // Bottom border row, inside the corners — the same content rect the chat
     // prompt uses for its info line.

crates/codegen/kigi-tui/src/views/dashboard/row.rs

@@ -1721,8 +1721,6 @@ mod tests {
             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,