Implement MVP: Anonymous feedback submission (User Story 1)

Complete implementation of Phase 1-3 (64 tasks):
- Phase 1: Project setup with Flask, pytest, configuration
- Phase 2: Core infrastructure (auth, models, services, testing)
- Phase 3: Anonymous feedback submission with file uploads

Features:
- Anonymous feedback submission (text and/or up to 3 file attachments)
- Multi-language support (any language accepted)
- File validation (type, size) and virus scanning (ClamAV)
- Product management with active/archived status
- File-based storage with YAML metadata
- User authentication system (Flask-Login)
- CSRF protection and rate limiting
- Test coverage: 10 passing tests (contract + integration)

Security:
- No IP address logging (FR-055 compliance)
- File type whitelist and size limits (10MB max)
- Virus scanning with graceful degradation
- Filename sanitization and secure storage

Test Results:
- 8 contract tests passed
- 2 integration tests passed
- End-to-end workflow verified

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

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

app/routes/submission.py

@@ -0,0 +1,100 @@
+"""Submission routes - anonymous feedback submission"""
+from flask import Blueprint, render_template, request, redirect, url_for, flash, abort
+from app.models.product import Product
+from app.services.feedback_storage import FeedbackStorageService
+from app.utils.file_validator import validate_file, scan_file_for_viruses
+
+
+bp = Blueprint('submission', __name__, url_prefix='/submit')
+
+
+@bp.route('/<product_slug>', methods=['GET'])
+def form(product_slug):
+    """Display feedback submission form
+
+    Args:
+        product_slug: Product submission URL slug
+
+    Returns:
+        Rendered submission form template or 404
+    """
+    # Load product by slug
+    product = Product.get_by_slug(product_slug)
+
+    if not product:
+        abort(404, description="Product not found")
+
+    # Check if product is archived
+    if product.is_archived():
+        abort(404, description="This product is no longer accepting feedback")
+
+    return render_template('submission/form.html', product=product)
+
+
+@bp.route('/<product_slug>', methods=['POST'])
+def submit(product_slug):
+    """Process feedback submission
+
+    Args:
+        product_slug: Product submission URL slug
+
+    Returns:
+        Redirect to success page or error page
+    """
+    # Load product by slug
+    product = Product.get_by_slug(product_slug)
+
+    if not product:
+        abort(404, description="Product not found")
+
+    # Check if product is archived
+    if product.is_archived():
+        abort(404, description="This product is no longer accepting feedback")
+
+    # Get form data
+    feedback_text = request.form.get('feedback_text', '').strip()
+
+    # Get uploaded files
+    uploaded_files = request.files.getlist('files')
+    # Filter out empty file inputs
+    files = [f for f in uploaded_files if f and f.filename != '']
+
+    # Validation: Must provide either text or files
+    if not feedback_text and not files:
+        abort(400, description="Please provide either feedback text or attachments")
+
+    # Validation: Maximum 3 files
+    if len(files) > 3:
+        abort(400, description="Maximum 3 attachments allowed")
+
+    # Validate each file
+    for file in files:
+        is_valid, error_message = validate_file(file)
+        if not is_valid:
+            abort(400, description=error_message)
+
+        # Scan for viruses
+        is_clean, virus_message = scan_file_for_viruses(file)
+        if not is_clean:
+            abort(400, description=f"File rejected: {virus_message}")
+
+    # Save feedback
+    try:
+        feedback = FeedbackStorageService.save_complete_feedback(
+            product_id=product.product_id,
+            content_text=feedback_text if feedback_text else None,
+            files=files if files else None
+        )
+
+        return render_template('submission/success.html',
+                             product=product,
+                             feedback_id=feedback.feedback_id)
+
+    except Exception as e:
+        # Log error
+        from flask import current_app
+        current_app.logger.error(f"Error saving feedback: {e}")
+
+        return render_template('submission/error.html',
+                             product=product,
+                             error_message="An error occurred while saving your feedback. Please try again."), 500