Phase 6: Expand market rates and enhance AI investment recommendations

- Rate fetcher now scrapes CD, Money Market, and High Yield Savings rates
  from Bankrate.com with pauses between fetches to avoid rate limiting
- Historical rate data is preserved (no longer deleted on each fetch)
- Database migration adds rate_type column and tenant ai_recommendations table
- Backend returns market rates grouped by type with latest-batch-only queries
- AI prompt now includes all three rate types for comprehensive analysis
- AI recommendations are saved per-tenant for retrieval on page load
- Frontend: "Market CD Rates" replaced with "Today's Market Rates" tabbed view
- Rates section is collapsible (expanded by default) to save screen space
- Saved recommendations load automatically with "Last Updated" timestamp

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/src/modules/investment-planning/investment-planning.controller.ts

@@ -17,11 +17,23 @@ export class InvestmentPlanningController {
   }
 
   @Get('cd-rates')
-  @ApiOperation({ summary: 'Get latest CD rates from market data' })
+  @ApiOperation({ summary: 'Get latest CD rates from market data (backward compat)' })
   getCdRates() {
     return this.service.getCdRates();
   }
 
+  @Get('market-rates')
+  @ApiOperation({ summary: 'Get all market rates grouped by type (CD, Money Market, High Yield Savings)' })
+  getMarketRates() {
+    return this.service.getMarketRates();
+  }
+
+  @Get('saved-recommendation')
+  @ApiOperation({ summary: 'Get the latest saved AI recommendation for this tenant' })
+  getSavedRecommendation() {
+    return this.service.getSavedRecommendation();
+  }
+
   @Post('recommendations')
   @ApiOperation({ summary: 'Get AI-powered investment recommendations' })
   getRecommendations(@Req() req: any) {