Electron App: Preview panel

[jongio]

Overview

Resizable preview panel showing full session details with rich markdown conversation rendering.

Acceptance Criteria

• Resizable panel (drag handle between list and preview)
• Position options: right (default), left, top, bottom — via setting
• Toggle visibility with 'p' key
• Metadata header: session ID (click to copy), repo, branch, cwd, timestamps, host type
• Conversation view: markdown-rendered bubbles (user = right/colored, assistant = left)
• Syntax highlighting in code blocks (react-syntax-highlighter)
• Conversation sort toggle: newest first / oldest first
• Checkpoints section: expandable cards (title, overview, up to 5)
• Files section: list of touched files (up to 5, with tool name)
• Refs section: PRs, issues, commits (up to 5, clickable links)
• Plan view: toggle between session detail and plan.md content
• Work status display: task completion progress, remaining items
• Text selection: click-drag to select text, copy on Ctrl+C
• Copy all preview content with 'y' key
• Scroll indicators (top/bottom fade when more content)
• Empty state when no session selected

Design Notes

• Use react-markdown + remark-gfm for full GFM support
• Conversation bubbles styled differently for user vs assistant
• Smooth scroll, snap to sections on keyboard navigation
• Minimum width: 300px, maximum: 70% of window