feat: enhance toast notifications with configurable timeouts and additional operations

[jellydn]

Summary

🔄 Stack PR: This builds on PR #202 and should be merged after #202

🎯 Major Features

✅ Toast notifications for resume operations (worktree setup feedback)
✅ Toast notifications for pause/checkout operations (worktree cleanup feedback)
✅ Configurable toast dismiss timeouts via user configuration
✅ Unified 3-second default timeout for better readability

🚨 Critical Bug Fix

✅ Fixed session auto-deletion after terminal restart - Previously, closing terminal tab and restarting cs would auto-pause and delete existing sessions. This is now fixed.

Changes

🆕 New Operations Coverage

• Resume Operations (app.go:811-817): Shows "Resuming session..." → "Session resumed successfully!"
• Pause/Checkout Operations (app.go:796-802): Shows "Pausing session..." → "Session paused successfully!"

🐛 Critical Bug Fix Details

Problem: After terminal restart, sessions were being deleted instead of recovered
Root Cause: Start(false) directly called tmuxSession.Restore() without checking if tmux session exists
Solution: Added proper session existence check like Resume() method - creates new tmux session if old one is gone

Impact: Sessions now survive terminal restarts instead of being destroyed

⚙️ Configurable Timeouts

Users can customize toast durations in ~/.claude-squad/config.json:

{
  "toast_timeouts": {
    "info": 3000,    // milliseconds (3 seconds default)
    "success": 3000, // milliseconds (3 seconds default) 
    "warning": 3000, // milliseconds (3 seconds default)
    "error": 3000    // milliseconds (3 seconds default)
  }
}

📚 Enhanced Documentation

• Updated ADR with new features and configuration options
• Documented integration points for resume/pause operations
• Added configuration examples and usage guidelines

Technical Implementation

Config System Integration

• Added ToastTimeouts struct to main Config with JSON serialization
• Updated NewToastManager(config) to accept configuration
• Modified timeout logic to use config values instead of hardcoded durations

Session Recovery Fix

// Before: Direct restore (fails after terminal restart)  
if err := tmuxSession.Restore(); err != nil {
    return err  // This would kill the session
}

// After: Check existence first (survives terminal restart)
if tmuxSession.DoesSessionExist() {
    tmuxSession.Restore()  // Restore if exists
} else {
    tmuxSession.Start()    // Create new if gone
}

Test Plan

• All existing tests pass with configurable toast manager
• Resume operations show appropriate toast feedback
• Pause/checkout operations show appropriate toast feedback
• Config system loads and applies custom timeouts correctly
• Default 3-second timeout provides optimal user experience
• Session recovery works after terminal restart
• Test files updated to use config.DefaultConfig() for initialization

Stack Dependencies

⚠️ Merge Order:

1. ⬅️ Base Toast System: Add 'b' key for branch-based session creation #202
2. ➡️ This PR: Configurable timeouts + resume/pause operations + session recovery fix

Files Changed

• config/config.go - Added toast timeout configuration
• ui/overlay/toast.go - Enhanced with configurable timeouts
• app/app.go - Added resume/pause operation toasts
• session/instance.go - Fixed session recovery after terminal restart
• docs/adr/001-toast-notifications.md - Updated documentation
• Test files - Updated for configurable toast manager

🤖 Generated with Claude Code