refactor(core): implement multi-assessment type architecture

Transform single friendship assessment into extensible multi-type platform

BREAKING CHANGE: Assessment data structure updated with assessmentType field

Features:
- Add assessment configuration system with registry pattern
- Create generic scoring algorithm in lib/core/scoring.ts
- Implement dynamic assessment loading in stores
- Add type filtering and badges in history page
- Support multiple assessment types (friendship, family)

Architecture Changes:
- New lib/assessments/ structure with plugin-based configs
- Dynamic routing with app/assess/[type]/ for type-specific assessments
- Type-safe assessment configurations with TypeScript
- Backward compatible data migration for existing assessments

Components:
- Create assessment type selection page (app/assess/page.tsx)
- Refactor assessment page to support dynamic types
- Update results page to render based on assessment type
- Enhance history page with type filtering dropdown

Assessment Types:
- Migrate friendship assessment to new structure (20 questions, 10 categories)
- Add family relationship assessment (16 questions, 8 categories)

Developer Experience:
- Add new assessment type in 4 simple steps
- No component changes needed for new types
- Full TypeScript type safety
- Comprehensive CLAUDE.md documentation

🤖 Generated with Claude Code (https://claude.com/claude-code)

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

Author: ChanMeng666

CLAUDE.md

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+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+FriendScope is a Next.js 15 application that provides scientific friendship assessments through a client-side architecture. The application evaluates friendships across 10 psychological categories using a 20-question assessment, providing users with detailed analytics, historical tracking, and personalized recommendations - all while maintaining complete privacy through local storage.
+
+**Tech Stack:**
+- **Framework**: Next.js 15 with App Router, React 19, TypeScript 5
+- **Styling**: Tailwind CSS + shadcn/ui components
+- **State Management**: Zustand with persist middleware
+- **Charts**: Recharts + ApexCharts
+- **Animations**: Framer Motion + Lottie React
+- **PDF Export**: jsPDF
+- **Deployment**: Vercel
+
+## Development Commands
+
+```bash
+# Development
+npm run dev          # Start dev server at http://localhost:3000
+npm run build        # Build for production
+npm run start        # Start production server
+npm run lint         # Run ESLint
+
+# Package Manager
+npm install          # Install dependencies (also: yarn, pnpm)
+```
+
+## Architecture
+
+### Core Assessment System
+
+The assessment engine (`lib/assessment.ts`) is the heart of the application:
+
+- **20 questions across 10 categories**: Each question has a weight (1.0-1.5) reflecting psychological importance
+- **10 assessment categories**:
+  - Trust & Honesty (weight: 1.5) - Core foundation
+  - Emotional Support (weight: 1.2)
+  - Communication (weight: 1.0)
+  - Boundaries (weight: 1.3)
+  - Reciprocity (weight: 1.1)
+  - Conflict Resolution (weight: 1.2)
+  - Growth & Development (weight: 1.0)
+  - Values Alignment (weight: 1.4)
+  - Respect & Recognition (weight: 1.2)
+  - Reliability (weight: 1.3)
+
+- **Scoring algorithm**: Weighted calculation that converts 7-point Likert scale responses into category scores (0-100), then averages to overall score
+- **Health assessment thresholds**: Excellent (85+), Good (70-84), Concerning (50-69), Unhealthy (30-49), Toxic (<30)
+
+### State Management Architecture
+
+**Two separate Zustand stores with different purposes:**
+
+1. **`lib/store.ts`** - Assessment State (non-persistent):
+   - Manages current assessment session
+   - Tracks question progression and answers
+   - Resets on completion
+   - No persistence - temporary state only
+
+2. **`lib/history-store.ts`** - History State (persistent):
+   - Persists completed assessments to localStorage
+   - Manages assessment history (max 50 entries)
+   - Provides CRUD operations for historical data
+   - Key: `friendship-assessment-history`
+
+**Critical distinction**: Assessment state is transient; only completed assessments are saved to history store.
+
+### Data Flow
+
+```
+User Input → Assessment Store (temp) → Calculate Scores → Save to History Store (persistent) → Visualization
+```
+
+1. User takes assessment (`app/assess/page.tsx`)
+2. Answers stored in temporary assessment store (`lib/store.ts`)
+3. On completion, scores calculated (`lib/assessment.ts:calculateScores`)
+4. Result saved to history store with localStorage persistence (`lib/history-store.ts`)
+5. User redirected to results page (`app/results/[id]/page.tsx`)
+
+### Component Structure
+
+```
+app/
+├── page.tsx                 # Landing page
+├── assess/page.tsx          # Assessment interface (stepper through 20 questions)
+├── results/[id]/page.tsx    # Individual result detail page
+├── results/page.tsx         # All results overview
+├── history/page.tsx         # Assessment history with comparison
+├── about/page.tsx           # Mission and scientific foundation
+├── resources/page.tsx       # Professional support resources
+└── layout.tsx              # Root layout with Header/Footer
+
+components/
+├── ui/                     # shadcn/ui base components
+├── layout/                 # Header.tsx, Footer.tsx
+├── dialogs/                # ShareDialog.tsx
+├── ComparisonChart.tsx     # Multi-assessment comparison visualization
+├── FriendInfoDialog.tsx    # Assessment metadata entry
+├── GEOHead.tsx            # SEO/meta tags
+├── GEODashboard.tsx       # Analytics dashboard
+└── LottieAnimation.tsx     # Animation wrapper
+
+lib/
+├── assessment.ts           # Questions, scoring, health assessment logic
+├── assessment-utils.ts     # PDF generation, share functionality
+├── store.ts               # Assessment state (non-persistent)
+├── history-store.ts       # History state (persistent to localStorage)
+├── geo-analytics.ts       # Analytics utilities
+├── svg-generator.ts       # SVG export functionality
+├── fonts.ts               # Font configurations
+└── utils.ts               # General utilities (cn, etc.)
+
+types/
+└── assessment.ts          # AssessmentResult interface
+```
+
+## Key Implementation Details
+
+### Assessment Question Format
+
+Each question in `lib/assessment.ts` follows this structure:
+```typescript
+{
+  id: number,              // 1-20
+  text: string,            // Question text
+  options: string[],       // 7-point Likert scale (standardOptions)
+  category: string,        // One of 10 categories
+  weight: number          // 1.0-1.5 (psychological importance)
+}
+```
+
+### Score Calculation
+
+The `calculateScores` function in `lib/assessment.ts:182`:
+1. Groups answers by category
+2. Converts each answer to weighted score: `((optionsLength - 1 - optionIndex) / (optionsLength - 1)) * 100 * weight`
+3. Calculates category averages
+4. Overall score = mean of all category averages
+
+### localStorage Schema
+
+```typescript
+// Key: friendship-assessment-history
+{
+  state: {
+    assessments: AssessmentResult[] // Max 50 entries
+  },
+  version: 0
+}
+```
+
+### TypeScript Path Aliases
+
+Uses `@/*` alias for imports (e.g., `@/lib/assessment`, `@/components/ui/button`)
+
+## Privacy-First Architecture
+
+**Critical**: All data processing happens client-side:
+- No backend API calls
+- No user authentication/tracking
+- All assessments stored in browser localStorage
+- No external analytics (except Next.js built-in)
+- PDF generation and sharing are client-side only
+
+When adding features, maintain this privacy-first approach.
+
+## Styling Conventions
+
+- **Tailwind CSS** for utility-first styling
+- **shadcn/ui** for component primitives (never modify these directly)
+- **Framer Motion** for page transitions and animations
+- **Responsive design**: Mobile-first approach
+- **Dark mode**: Not currently implemented but Tailwind is configured for it
+
+## Common Development Tasks
+
+### Adding a New Assessment Question
+
+1. Add question to `lib/assessment.ts:questions` array
+2. Ensure it uses `standardOptions`
+3. Assign to existing category or create new one
+4. Set appropriate weight (1.0-1.5)
+5. Update category descriptions if new category
+
+### Modifying Scoring Algorithm
+
+All scoring logic is in `lib/assessment.ts:calculateScores`. Consider:
+- Weighted vs unweighted scores
+- Category average calculations
+- Overall score aggregation
+- Impact on existing assessments
+
+### Adding New Visualizations
+
+Charts are built with Recharts/ApexCharts:
+- See `app/results/[id]/page.tsx` for radar chart implementation
+- See `components/ComparisonChart.tsx` for multi-assessment comparisons
+- Keep charts responsive and accessible
+
+### Extending History Features
+
+History store (`lib/history-store.ts`) supports:
+- Adding/removing assessments
+- Retrieving by ID
+- Clearing all history
+- Automatic 50-entry limit
+
+## Scientific Accuracy
+
+The assessment is based on psychological research. When modifying:
+- Maintain evidence-based question design
+- Preserve weighted scoring reflecting research importance
+- Keep 7-point Likert scale for statistical validity
+- Ensure health assessment thresholds are meaningful
+
+## Performance Considerations
+
+- Next.js automatic code splitting by route
+- Lazy load heavy components (charts, animations)
+- Optimize images with Next.js Image component
+- localStorage operations are synchronous - keep minimal
+- Zustand provides efficient re-renders
+
+## Testing Assessment Flow
+
+Manual testing checklist:
+1. Start assessment on `/assess`
+2. Answer all 20 questions
+3. Enter friend name and notes in dialog
+4. Verify score calculation
+5. Check localStorage persistence
+6. Test PDF export
+7. Verify history tracking
+8. Test comparison charts with multiple assessments
+
+## Known Constraints
+
+- Maximum 50 assessments in history (oldest auto-deleted)
+- localStorage size limits vary by browser (~5-10MB)
+- PDF generation is client-side only (limited styling)
+- No backend means no cross-device sync
+- Assessment questions are English-only
+
+## Deployment
+
+Project is configured for Vercel deployment:
+- No environment variables required
+- Automatic deployments on push to master
+- Edge runtime not used (client-side rendering)
+- No serverless functions needed