feat: add keyboard shortcut to toggle dangerous mode for running tasks

[bborn]

Summary

Adds a keyboard shortcut (!) in the task detail view to restart a running Claude instance with --dangerously-skip-permissions flag enabled.

This allows users to enable dangerous mode for a specific running task without restarting the daemon or affecting other tasks.

Changes Made

UI Changes

• Added ToggleDangerous key binding mapped to ! key
• Added help text showing ! dangerous mode when task is processing or blocked
• Wire up keyboard handler to call new executor method

Executor Changes

• Implemented ResumeDangerous() method that:
  • Kills the current Claude tmux window for the task
  • Restarts Claude with --resume <sessionID> --dangerously-skip-permissions
  • Preserves the Claude session state for continuity
  • Only works if task has a Claude session ID

App Model Changes

• Added toggleDangerousMode() command to handle the keyboard shortcut
• Added taskDangerousModeToggledMsg message type for UI updates

How It Works

1. User presses ! while viewing a processing or blocked task
2. The executor kills the current Claude tmux window
3. A new Claude process starts with the same session ID but with --dangerously-skip-permissions flag
4. Claude resumes from where it left off, but now without permission prompts
5. Task execution log shows "Claude restarted in dangerous mode"

Testing

• Code compiles without errors
• Keyboard shortcut only shows for processing/blocked tasks
• Method preserves Claude session for continuity

Related

Closes #302

Notes

• This only affects the specific task, not the global daemon mode
• The dangerous flag is forced regardless of WORKTREE_DANGEROUS_MODE setting
• The feature requires an active Claude session (task must have been started at least once)