Add implementation plan for product selection landing page (Feature 002)

Completed planning phases 0 and 1 for simple landing page feature.

## Plan Overview:

**Approach**: Minimal addition to existing Flask app - reuse Product model,
add one route, one template. No new dependencies or complexity.

**Constitution Check**: ✅ All 5 principles satisfied
- Specification-first development (spec.md complete)
- Test-first discipline (TDD workflow defined)
- Independent user stories (3 stories, all independently testable)
- Simplicity (reuses existing Flask/Jinja2/Product architecture)
- Documentation as code (all artifacts in specs/002-product-list/)

## Artifacts Created:

### Phase 0: Research (research.md)
- Reuses infrastructure from feature 001 (Flask, Jinja2, file storage)
- Single new decision: Product.load_active() method for filtering/sorting
- Performance analysis: <100ms for 100 products (well under 1s target)

### Phase 1: Design & Contracts
- **data-model.md**: Documents Product model extension (load_active method)
- **contracts/landing-page.yaml**: OpenAPI contract for GET / route
- **quickstart.md**: Developer implementation guide with:
  - Step-by-step implementation checklist
  - Code snippets for route, template, tests
  - TDD workflow (write tests → verify fail → implement → pass)
  - Manual verification checklist

### Agent Context
- Updated CLAUDE.md with feature technologies (no new tech added)

## Implementation Summary:

**New Files** (to be created):
- app/routes/landing.py - Landing page route handler
- app/templates/landing/index.html - Product list template
- tests/contract/test_landing_routes.py - Contract tests (6 scenarios)
- tests/integration/test_landing_flow.py - User journey test

**Modified Files**:
- app/models/product.py - Add load_active() class method
- app/__init__.py - Register landing blueprint

## Key Technical Decisions:

1. **Filtering**: status=='active' AND submission_url_slug exists
2. **Sorting**: Alphabetical by name (case-insensitive), then product_id
3. **Empty State**: "No products are currently accepting feedback" message
4. **XSS Prevention**: Jinja2 auto-escaping (no manual escaping needed)
5. **Performance**: File I/O sufficient (<1s for 100 products, no caching)

## Next Steps:

1. Run /speckit.tasks to generate tasks.md
2. Run /speckit.implement to execute TDD workflow
3. Verify all tests pass
4. Manual verification checklist
5. Create pull request

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

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

specs/002-product-list/data-model.md

@@ -0,0 +1,147 @@
+# Data Model: Product Selection Landing Page
+
+**Feature**: 002-product-list | **Date**: 2025-10-17
+
+## Overview
+
+This feature reuses the existing **Product** entity from feature 001-build-an-application with a minor extension. No new entities are created.
+
+## Existing Entity: Product
+
+**Source**: `app/models/product.py` (from feature 001)
+
+**Attributes** (relevant to this feature):
+
+| Attribute | Type | Required | Description |
+|-----------|------|----------|-------------|
+| `product_id` | str | Yes | Unique identifier (e.g., "001-acme-app") |
+| `name` | str | Yes | Display name for the product |
+| `submission_url_slug` | str | Yes | URL segment for submission form |
+| `status` | str | Yes | "active" or "archived" |
+| `description` | str | No | Brief product description (optional) |
+
+**Storage**: File-based YAML at `data/products/{product-id}/config.yaml`
+
+**Example**:
+```yaml
+product_id: "001-acme-app"
+name: "Acme Application"
+submission_url_slug: "acme-app"
+status: "active"
+description: "Enterprise resource planning system"
+```
+
+---
+
+## Model Extension
+
+### New Class Method: `load_active()`
+
+**Purpose**: Load and return only active products with valid submission URLs, sorted for display.
+
+**Signature**:
+```python
+@classmethod
+def load_active(cls) -> list[Product]:
+    """Load all active products, sorted alphabetically by name then product_id."""
+```
+
+**Returns**: List of Product instances where:
+- `status == 'active'`
+- `submission_url_slug` is present and valid
+- Sorted by: `(name.lower(), product_id)`
+
+**Implementation Location**: `app/models/product.py`
+
+**Usage Example**:
+```python
+from app.models.product import Product
+
+# In route handler
+products = Product.load_active()
+# Returns sorted list of active products ready for display
+```
+
+---
+
+## Data Flow
+
+### Landing Page Load Sequence
+
+1. **Request**: User navigates to `/`
+2. **Route Handler**: `app/routes/landing.py`
+   - Calls `Product.load_active()`
+3. **Data Loading**: Product model
+   - Reads all `data/products/*/config.yaml` files
+   - Filters: `status == 'active'` AND `submission_url_slug` exists
+   - Sorts: By `(name.lower(), product_id)`
+4. **Response**: Render template with product list
+   - Pass `products` to `templates/landing/index.html`
+   - Template loops over products, displays name/description/link
+
+### Diagram
+
+```
+User → GET / → landing.py → Product.load_active() → [Product, Product, ...]
+                                  ↓
+                            Templates (Jinja2) → HTML Response → User
+```
+
+---
+
+## Validation Rules
+
+### Product Visibility (for landing page)
+
+A product is **visible** on the landing page if and only if:
+1. `status == 'active'` (FR-003)
+2. `submission_url_slug` is not None/empty (FR-015)
+
+Products failing either condition are **excluded** from the list.
+
+### Sorting Rules (FR-009)
+
+Products are sorted by:
+1. **Primary**: `name` (case-insensitive alphabetical)
+2. **Secondary**: `product_id` (alphabetical, for ties)
+
+**Examples**:
+- Input: `[{"name": "Zebra", "product_id": "001"}, {"name": "Apple", "product_id": "002"}]`
+- Output: `[{"name": "Apple", ...}, {"name": "Zebra", ...}]`
+
+- Input: `[{"name": "App", "product_id": "002"}, {"name": "App", "product_id": "001"}]`
+- Output: `[{"name": "App", "product_id": "001"}, {"name": "App", "product_id": "002"}]`
+
+---
+
+## No New Entities
+
+This feature introduces **no new entities**. All data structures are reused from feature 001:
+- Product entity (extended with `load_active()` method only)
+- File-based YAML storage (unchanged)
+- No database tables, no new data files
+
+---
+
+## Testing Considerations
+
+### Test Data Requirements
+
+For comprehensive testing, create products with:
+- Various statuses: "active", "archived"
+- With/without descriptions
+- With/without valid `submission_url_slug`
+- Duplicate names (to test secondary sort)
+- Various name cases ("Apple", "apple", "APPLE")
+
+### Expected Behaviors
+
+| Scenario | Expected Result |
+|----------|----------------|
+| Product with `status: active` | Included in list |
+| Product with `status: archived` | Excluded from list |
+| Product with missing `submission_url_slug` | Excluded from list |
+| Products with same name | Sorted by product_id |
+| Empty product directory | Returns empty list |
+
+**Reference Tests**: See `tests/contract/test_landing_routes.py` for data model validation tests.