v0.4.2 — Copilot Support, Mermaid Overhaul, Data Tables

Major feature additions including GitHub Copilot as an alternative provider, completely rebuilt Mermaid diagram engine, native data tables, and numerous stability fixes.

🤖 GitHub Copilot Support

• Added GitHub Copilot as an alternative LLM provider with full OAuth authentication
• New connection screens for configuring and switching between providers
• Provider-specific icons for Claude, Copilot, OpenAI, Ollama, OpenRouter, and Vercel
• Session lock warnings when switching between providers

📊 Native Data Tables & Spreadsheets

• New datatable block for sortable, filterable data displays
• New spreadsheet block for Excel-style grids with export support
• transform_data tool for processing large datasets via scripts
• File-backed tables via src field for datasets with 20+ rows

📐 Mermaid Diagram Engine Overhaul

• Replaced Dagre layout engine with ELK for better graph layouts
• Improved edge routing, bundling, and approach directions
• Multiline label support across all diagram types
• New shape system with circles, diamonds, hexagons, stadiums, and state shapes
• ASCII rendering improvements with ANSI color support
• Better subgraph direction overrides and disconnected graph handling

🔧 Connection & Provider Improvements

• Refined LLM connection configuration screens
• Updated to Claude Opus 4.6 as default model
• OAuth token refresh improvements
• Multi-header authentication support for API sources

🔌 Codex Integration Fixes

• Fixed bundled Codex binary path resolution in packaged apps
• Moved codex.exe to extraResources on Windows to prevent EBUSY errors
• Skill content injection for Codex sessions (no longer relies on native discovery)
• Silent failure and title generation fixes for OAuth sessions
• Build verification now checks for Codex binary in SDK bundling stage

🐛 Bug Fixes

• Fixed OAuth browser launch ENOENT error using shell.openExternal
• Fixed workspace theme not updating on workspace switch
• Fixed dock badge and window icon paths in packaged app
• Fixed Sentry to only send console errors, not warnings
• Fixed PowerShell install script to use YAML manifests
• Fixed renderer importing Node.js fs module in browser bundle
• Fixed metadata race condition in session persistence
• Consolidated large response handling

📦 Dependency Updates

• Bumped claude-agent-sdk to ^0.2.37
• Bumped electron-updater to ^6.8.0
• Added elkjs for diagram layouts

🏗️ Build & Infrastructure

• Default workspace sources configuration
• Unified title generation through agent SDK infrastructure
• Removed deprecated PlanningAdvisor
• Removed headless mode (consolidated into main agent flow)