feat: introduce workflow management tools and commands

- Added new workflow commands: `/workflow` to open the workflow panel and `/workflow run <prompt>` to execute workflows.
- Implemented `spawn_agents` and `spawn_pipeline` tools for parallel and sequential task execution, respectively.
- Enhanced workflow engine to handle real-time agent status updates and display in the UI.
- Updated workflow panel to show agent statuses, findings count, and session counters.
- Refactored existing code to integrate new workflow functionalities and improve overall structure.

src/resources.rs

@@ -22,12 +22,14 @@ Navigation:
   Up/Down      History navigation
 
 Input:
-  /help        Show help
-  /clear       Clear screen
-  /model       Select AI model provider
-  /exit        Exit application
-  /settings    Open settings
-  /session     Session management
+  /help               Show help
+  /clear              Clear screen
+  /model              Select AI model provider
+  /workflow           Open workflow panel
+  /workflow run <p>   Run a workflow with prompt <p>
+  /mode workflow      Open workflow panel
+  /compact            Compact conversation history
+  /exit               Exit application
 
 Commands:
   Any text is sent to the AI assistant as a prompt.