feat(questions): implement questions app NestJS backend

Complete backend implementation for the AI-powered research assistant app:

Database Schema (Drizzle ORM):
- collections: Organize questions into folders with colors and icons
- questions: User questions with status, priority, tags, and research depth
- research_results: Results from mana-search service with summaries and key points
- sources: Extracted content from web search results
- answers: AI-generated answers with ratings and citations

NestJS Modules:
- QuestionModule: CRUD operations with filtering, pagination, and status management
- CollectionModule: Collection management with reordering and question counts
- ResearchModule: Integration with mana-search microservice for web search
- AnswerModule: Answer management with ratings and acceptance tracking
- SourceModule: Source content retrieval and management
- HealthModule: Health checks for database and search service

Features:
- Full JWT authentication via @manacore/shared-nestjs-auth
- Research depths: quick (5 sources), standard (15), deep (30)
- Automatic content extraction and summarization
- Follow-up question generation

Also updated:
- Root package.json: Added questions:* development scripts
- setup-databases.sh: Added questions database setup

https://claude.ai/code/session_01Rk3YVJCU3nM8uvVPghRz6r

apps/questions/package.json

@@ -0,0 +1,9 @@
+{
+	"name": "questions",
+	"version": "1.0.0",
+	"private": true,
+	"description": "Questions app - Collect questions and research answers",
+	"scripts": {
+		"dev": "turbo run dev"
+	}
+}