feat: Implement slash command functionality in the orchestrator

- Refactored NodePalette to remove unused templates and streamline the UI.
- Enhanced PropertyPanel to support slash commands with input fields for command name and arguments.
- Introduced TagEditor for inline variable editing and custom template creation.
- Updated PromptTemplateNode to display slash command badges and instructions.
- Modified flow types to include slashCommand and slashArgs for structured execution.
- Adjusted flow executor to construct instructions based on slash command fields.

ccw/frontend/src/locales/en/orchestrator.json

@@ -164,7 +164,10 @@
     "placeholders": {
       "nodeLabel": "Node label",
       "instruction": "e.g., Execute /workflow:plan for login feature\nor: Analyze code architecture\nor: Save {{analysis}} to ./output/result.json",
-      "outputName": "e.g., analysis, plan, result"
+      "outputName": "e.g., analysis, plan, result",
+      "slashCommand": "Select a command...",
+      "slashArgs": "Enter arguments...",
+      "additionalInstruction": "Additional instructions or context for the command..."
     },
     "labels": {
       "label": "Label",
@@ -172,7 +175,10 @@
       "outputName": "Output Name",
       "tool": "CLI Tool",
       "mode": "Execution Mode",
-      "contextRefs": "Context References"
+      "contextRefs": "Context References",
+      "slashCommand": "Slash Command",
+      "slashArgs": "Arguments",
+      "additionalInstruction": "Additional Context (optional)"
     },
     "options": {
       "toolNone": "None (auto-select)",