feat(ai): add Grok CLI as a Desktop no-API-key provider

* feat(ai): add Grok CLI as a Desktop no-API-key provider

Add grok-cli alongside Codex/Claude Code/Pi, with path/env settings,
isolated MCP-scoped headless runs, model listing, and connection test.

* feat(ai): expose Grok CLI reasoning effort like Codex

Attach low/medium/high effort capabilities to Grok models for the
assistant effort menu, wire resolve_model_effort for grok-cli, and
use the monochrome Grok mark icon.

* i18n: add Grok CLI error messages for remaining locales

Fill grokCli* cliErrors strings in es, it, ja, ko, pt-BR, and zh-TW
to match en/zh-CN and satisfy i18n autofill CI.

* fix(ai): align Grok CLI headless with official Build flags

Address review feedback on PR #5494:
- Use streaming-json + CliAgentJsonlDialect::GrokStreamingJson
- Switch permission to --always-approve and MCPTool(dbx__*) rules
- Prefer --effort over --reasoning-effort; keep --prompt-file

Verified with unit tests and a local headless e2e against grok 1.0.

* style(ai): fix rustfmt for Grok CLI provider files

* test(ai): fix Grok CLI entry in provider ordering spec

* fix(ai): harden grok CLI error wording and config schema

Add 'not signed in' to classify_grok_run_error and test_grok_connection
auth detection — real @xai-official/grok 1.0.0 emits this exact wording
on headless auth failure (verified against the shipped binary).

Remove invalid config.toml fields: permission_mode='always-approve'
(not a valid enum; auto-approve is driven by --always-approve flag) and
startup_timeout_sec/tool_timeout_sec/enabled_tools (not mcp_servers
schema fields per 'grok mcp add').

---------

Co-authored-by: t8y2 <1156263951@qq.com>

src-tauri/src/commands/ai.rs

@@ -241,6 +241,7 @@ fn resolve_cli_provider_config(mut config: AiConfig) -> AiConfig {
         AiProvider::PiAgentCli => (&mut config.pi_agent_cli_path, "pi"),
         AiProvider::OpenCodeCli => (&mut config.opencode_cli_path, "opencode"),
         AiProvider::CursorCli => (&mut config.cursor_cli_path, "agent"),
+        AiProvider::GrokCli => (&mut config.grok_cli_path, "grok"),
         _ => return config,
     };
     let command = path_slot.as_deref().map(str::trim).filter(|path| !path.is_empty()).unwrap_or(default_command);
@@ -330,6 +331,8 @@ mod tests {
             opencode_cli_env: Default::default(),
             cursor_cli_path: None,
             cursor_cli_env: Default::default(),
+            grok_cli_path: None,
+            grok_cli_env: Default::default(),
         }
     }