refactor: remove suggestions routes and related logic

This commit removes the suggestions routes and associated files from the server, streamlining the codebase. The `suggestionsModel` has been replaced with `ideationModel` across various components, including UI and service layers, to better reflect the updated functionality. Additionally, adjustments were made to ensure that the ideation service correctly utilizes the new model configuration.

- Deleted suggestions routes and their handlers.
- Updated references from `suggestionsModel` to `ideationModel` in settings and UI components.
- Refactored related logic in the ideation service to align with the new model structure.

apps/ui/src/components/views/settings-view/model-defaults/bulk-replace-dialog.tsx

@@ -42,7 +42,7 @@ const PHASE_LABELS: Record<PhaseModelKey, string> = {
   featureGenerationModel: 'Feature Generation',
   backlogPlanningModel: 'Backlog Planning',
   projectAnalysisModel: 'Project Analysis',
-  suggestionsModel: 'AI Suggestions',
+  ideationModel: 'Ideation',
   memoryExtractionModel: 'Memory Extraction',
 };
 

apps/ui/src/components/views/settings-view/model-defaults/model-defaults-section.tsx

@@ -67,9 +67,9 @@ const GENERATION_TASKS: PhaseConfig[] = [
     description: 'Analyzes project structure for suggestions',
   },
   {
-    key: 'suggestionsModel',
-    label: 'AI Suggestions',
-    description: 'Model for feature, refactoring, security, and performance suggestions',
+    key: 'ideationModel',
+    label: 'Ideation',
+    description: 'Model for ideation view (generating AI suggestions)',
   },
 ];