feat: Implement AI response feedback UI and complete high-priority features

Frontend Features:
- Add MessageFeedback component with thumbs up/down buttons
- Positive feedback submits immediately with success toast
- Negative feedback opens dialog for optional text input
- Integrate feedback buttons on all AI assistant messages
- Add success Snackbar confirmation message
- Translation keys added to ai.json (feedback section)

Backend Features:
- Add POST /api/v1/ai/feedback endpoint
- Create FeedbackDto with conversation ID validation
- Implement submitFeedback service method
- Store feedback in conversation metadata with timestamps
- Add audit logging for feedback submissions
- Fix conversationId regex validation to support nanoid format

Legal & Compliance:
- Implement complete EULA acceptance flow with modal
- Create reusable legal content components (Terms, Privacy, EULA)
- Add LegalDocumentViewer for nested modal viewing
- Cookie Consent Banner with GDPR compliance
- Legal pages with AppShell navigation
- EULA acceptance tracking in user entity

Branding Updates:
- Rebrand from "Maternal App" to "ParentFlow"
- Update all icons (72px to 512px) from high-res source
- PWA manifest updated with ParentFlow branding
- Contact email: hello@parentflow.com
- Address: Serbota 3, Bucharest, Romania

Bug Fixes:
- Fix chat endpoint validation (support nanoid conversation IDs)
- Fix EULA acceptance API call (use apiClient vs hardcoded localhost)
- Fix icon loading errors with proper PNG generation

Documentation:
- Mark 11 high-priority features as complete in REMAINING_FEATURES.md
- Update feature statistics: 73/139 complete (53%)
- All high-priority features now complete! 🎉

Files Changed:
Frontend: 21 files (components, pages, locales, icons)
Backend: 6 files (controller, service, DTOs, migrations)
Docs: 1 file (REMAINING_FEATURES.md)

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

maternal-web/components/features/ai-chat/AIChatInterface.tsx

@@ -54,6 +54,7 @@ import ReactMarkdown from 'react-markdown';
 import remarkGfm from 'remark-gfm';
 import { useTranslation } from '@/hooks/useTranslation';
 import { useStreamingChat } from '@/hooks/useStreamingChat';
+import { MessageFeedback } from './MessageFeedback';
 
 interface Message {
   id: string;
@@ -742,39 +743,57 @@ export const AIChatInterface: React.FC = () => {
                     }}
                   >
                     {message.role === 'assistant' ? (
-                      <Box
-                        sx={{
-                          '& p': { mb: 1 },
-                          '& strong': { fontWeight: 600 },
-                          '& ul, & ol': { pl: 2, mb: 1 },
-                          '& li': { mb: 0.5 },
-                          '& hr': { my: 2, borderColor: 'divider' },
-                          '& h1, & h2, & h3, & h4, & h5, & h6': {
-                            fontWeight: 600,
-                            mb: 1,
-                            mt: 1.5
-                          },
-                        }}
-                      >
-                        <ReactMarkdown remarkPlugins={[remarkGfm]}>
-                          {message.content}
-                        </ReactMarkdown>
-                      </Box>
+                      <>
+                        <Box
+                          sx={{
+                            '& p': { mb: 1 },
+                            '& strong': { fontWeight: 600 },
+                            '& ul, & ol': { pl: 2, mb: 1 },
+                            '& li': { mb: 0.5 },
+                            '& hr': { my: 2, borderColor: 'divider' },
+                            '& h1, & h2, & h3, & h4, & h5, & h6': {
+                              fontWeight: 600,
+                              mb: 1,
+                              mt: 1.5
+                            },
+                          }}
+                        >
+                          <ReactMarkdown remarkPlugins={[remarkGfm]}>
+                            {message.content}
+                          </ReactMarkdown>
+                        </Box>
+                        <Typography
+                          variant="caption"
+                          sx={{
+                            mt: 1,
+                            display: 'block',
+                            opacity: 0.7,
+                          }}
+                        >
+                          {message.timestamp.toLocaleTimeString()}
+                        </Typography>
+                        <MessageFeedback
+                          messageId={message.id}
+                          conversationId={currentConversationId}
+                        />
+                      </>
                     ) : (
-                      <Typography variant="body1" sx={{ whiteSpace: 'pre-wrap' }}>
-                        {message.content}
-                      </Typography>
+                      <>
+                        <Typography variant="body1" sx={{ whiteSpace: 'pre-wrap' }}>
+                          {message.content}
+                        </Typography>
+                        <Typography
+                          variant="caption"
+                          sx={{
+                            mt: 1,
+                            display: 'block',
+                            opacity: 0.7,
+                          }}
+                        >
+                          {message.timestamp.toLocaleTimeString()}
+                        </Typography>
+                      </>
                     )}
-                    <Typography
-                      variant="caption"
-                      sx={{
-                        mt: 1,
-                        display: 'block',
-                        opacity: 0.7,
-                      }}
-                    >
-                      {message.timestamp.toLocaleTimeString()}
-                    </Typography>
                   </Paper>
                   {message.role === 'user' && (
                     <Avatar sx={{ bgcolor: 'secondary.main', mt: 1 }}>