Replace session picker modal with instance welcome view

Transform the session picker from a modal into a comprehensive welcome screen that displays instance metadata, session history, and creation options. The new view provides full keyboard navigation, shows MCP server status, OpenCode binary path, and project information in a compact, space-efficient layout.

Key features:
- Instance metadata sidebar showing folder, project, VCS, version, binary path, MCP status, and server info
- Session list with keyboard navigation (↑↓, PgUp/PgDn, Home/End, Enter)
- Cmd+Enter shortcut to create new session from anywhere
- Compact design with efficient space usage
- Visual MCP server status indicators (running/stopped/error)
- Scrollable layout that keeps "New Session" section accessible

electron/preload/index.ts

@@ -2,9 +2,9 @@ import { contextBridge, ipcRenderer } from "electron"
 
 export interface ElectronAPI {
   selectFolder: () => Promise<string | null>
-  createInstance: (id: string, folder: string) => Promise<{ id: string; port: number; pid: number }>
+  createInstance: (id: string, folder: string) => Promise<{ id: string; port: number; pid: number; binaryPath: string }>
   stopInstance: (pid: number) => Promise<void>
-  onInstanceStarted: (callback: (data: { id: string; port: number; pid: number }) => void) => void
+  onInstanceStarted: (callback: (data: { id: string; port: number; pid: number; binaryPath: string }) => void) => void
   onInstanceError: (callback: (data: { id: string; error: string }) => void) => void
   onInstanceStopped: (callback: (data: { id: string }) => void) => void
   onInstanceLog: (