Fix Get started reopening after setup

[ProfSynapse]

The Get started accordion reopened for configured users because it required both internal chat and Claude Desktop MCP, and closing it was never saved. It now defaults closed when either setup path is configured and preserves the user's explicit open/closed choice across settings reloads.

Setup detection recognizes Codex MCP, the installed Nexus CLI, current and legacy MCP server names, CLI-authenticated providers, and keyless OpenAI-compatible endpoints. Desktop checks remain guarded and avoid shell/runtime probes.

Validation:

• Production build, ESLint, and mobile import gate passed.
• All 481 executed test suites passed across the full run and a rerun of three socket suites initially blocked by the sandbox.
• Regression tests cover setup paths and settings save/load; intentional policy and persistence mutations made the tests fail.
• Isolated Obsidian check verified actual DOM clicks and preference round-tripping with detached elements and in-memory settings. No installed plugin deployment was performed.