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.

libs/types/src/event.ts

@@ -25,7 +25,6 @@ export type EventType =
   | 'project:analysis-progress'
   | 'project:analysis-completed'
   | 'project:analysis-error'
-  | 'suggestions:event'
   | 'spec-regeneration:event'
   | 'issue-validation:event'
   | 'ideation:stream'

libs/types/src/settings.ts

@@ -598,8 +598,8 @@ export interface PhaseModelConfig {
   backlogPlanningModel: PhaseModelEntry;
   /** Model for analyzing project structure */
   projectAnalysisModel: PhaseModelEntry;
-  /** Model for AI suggestions (feature, refactoring, security, performance) */
-  suggestionsModel: PhaseModelEntry;
+  /** Model for ideation view (generating AI suggestions for features, security, performance) */
+  ideationModel: PhaseModelEntry;
 
   // Memory tasks - for learning extraction and memory operations
   /** Model for extracting learnings from completed agent sessions */
@@ -1235,7 +1235,7 @@ export const DEFAULT_PHASE_MODELS: PhaseModelConfig = {
   featureGenerationModel: { model: 'claude-sonnet' },
   backlogPlanningModel: { model: 'claude-sonnet' },
   projectAnalysisModel: { model: 'claude-sonnet' },
-  suggestionsModel: { model: 'claude-sonnet' },
+  ideationModel: { model: 'claude-sonnet' },
 
   // Memory - use fast model for learning extraction (cost-effective)
   memoryExtractionModel: { model: 'claude-haiku' },