feat: Phase B learning + hashtag profiles Pro-only lock

- Approve action saves post as reference example in character's content_rules
- Keep last 5 approved examples per character (auto-rotating)
- Inject last 3 approved examples as few-shot in LLM system prompt
- Lock YouTube/TikTok hashtag profile tabs for Freemium users (Pro only)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/app/routers/content.py

@@ -315,12 +315,28 @@ def approve_post(
     db: Session = Depends(get_db),
     current_user: User = Depends(get_current_user),
 ):
-    """Approve a post (set status to 'approved')."""
+    """Approve a post (set status to 'approved'). Also saves it as a reference example for the character."""
     post = db.query(Post).filter(Post.id == post_id, Post.user_id == current_user.id).first()
     if not post:
         raise HTTPException(status_code=404, detail="Post not found")
     post.status = "approved"
     post.updated_at = datetime.utcnow()
+
+    # Save as reference example for future few-shot learning (keep last 5 per character)
+    if post.text_content and post.character_id:
+        character = db.query(Character).filter(Character.id == post.character_id).first()
+        if character:
+            examples = character.content_rules or {}
+            approved_examples = examples.get("approved_examples", [])
+            approved_examples.append({
+                "platform": post.platform_hint or "general",
+                "text": post.text_content[:500],  # truncate for prompt efficiency
+            })
+            # Keep only last 5
+            examples["approved_examples"] = approved_examples[-5:]
+            character.content_rules = examples
+            character.updated_at = datetime.utcnow()
+
     db.commit()
     db.refresh(post)
     return post

backend/app/services/content.py

@@ -77,6 +77,15 @@ def generate_post_text(
             rules_text += "\nNON FARE MAI: " + " | ".join(dont_rules)
         system_parts.append(rules_text)
 
+    # Few-shot: approved examples from past posts
+    approved_examples = content_rules.get("approved_examples", [])
+    if approved_examples:
+        examples_text = "\nESEMPI DI POST APPROVATI (usa come riferimento per stile e tono):"
+        for i, ex in enumerate(approved_examples[-3:], 1):  # last 3 in prompt
+            plat = ex.get("platform", "")
+            examples_text += f"\n--- Esempio {i} ({plat}) ---\n{ex.get('text', '')}"
+        system_parts.append(examples_text)
+
     system_parts.extend([
         "\nYou create authentic, engaging content that resonates with your audience.",
         "Never reveal you are an AI. Write as {name} would naturally write.",

frontend/src/components/CharacterForm.jsx

@@ -1,6 +1,7 @@
 import { useState, useEffect } from 'react'
 import { useNavigate, useParams } from 'react-router-dom'
 import { api } from '../api'
+import { useAuth } from '../AuthContext'
 
 const EMPTY_FORM = {
   name: '',
@@ -37,6 +38,7 @@ export default function CharacterForm() {
   const { id } = useParams()
   const isEdit = Boolean(id)
   const navigate = useNavigate()
+  const { isPro } = useAuth()
 
   const [form, setForm] = useState(EMPTY_FORM)
   const [topicInput, setTopicInput] = useState('')
@@ -291,6 +293,7 @@ export default function CharacterForm() {
           <HashtagProfileEditor
             profiles={form.hashtag_profiles || {}}
             onChange={p => handleChange('hashtag_profiles', p)}
+            isPro={isPro}
           />
         </Section>
 
@@ -432,9 +435,11 @@ function RulesEditor({ doRules, dontRules, onChange }) {
   )
 }
 
-function HashtagProfileEditor({ profiles, onChange }) {
+function HashtagProfileEditor({ profiles, onChange, isPro }) {
   const [activeTab, setActiveTab] = useState('instagram')
   const [tagInput, setTagInput] = useState('')
+  const availablePlatforms = isPro ? HASHTAG_PLATFORMS : HASHTAG_PLATFORMS.filter(p => ['instagram', 'facebook'].includes(p))
+  const proOnlyPlatforms = ['youtube', 'tiktok']
 
   const getProfile = (platform) => profiles[platform] || { always: [], max_generated: 12 }
   const setProfile = (platform, profile) => onChange({ ...profiles, [platform]: profile })
@@ -460,18 +465,22 @@ function HashtagProfileEditor({ profiles, onChange }) {
   return (
     <div>
       <div style={{ display: 'flex', gap: '0', borderBottom: '2px solid var(--border)', marginBottom: '1rem' }}>
-        {HASHTAG_PLATFORMS.map(p => (
-          <button key={p} type="button" onClick={() => { setActiveTab(p); setTagInput('') }} style={{
+        {HASHTAG_PLATFORMS.map(p => {
+          const isLocked = !isPro && proOnlyPlatforms.includes(p)
+          return (
+          <button key={p} type="button" onClick={() => { if (!isLocked) { setActiveTab(p); setTagInput('') } }} style={{
             padding: '0.4rem 0.85rem', fontSize: '0.78rem', fontWeight: activeTab === p ? 700 : 400,
             fontFamily: "'DM Sans', sans-serif", border: 'none', cursor: 'pointer',
             backgroundColor: activeTab === p ? 'var(--surface)' : 'transparent',
-            color: activeTab === p ? 'var(--ink)' : 'var(--ink-muted)',
+            color: isLocked ? 'var(--border-strong)' : (activeTab === p ? 'var(--ink)' : 'var(--ink-muted)'),
             borderBottom: activeTab === p ? '2px solid var(--accent)' : '2px solid transparent',
             marginBottom: '-2px', textTransform: 'capitalize',
+            opacity: isLocked ? 0.5 : 1, cursor: isLocked ? 'not-allowed' : 'pointer',
           }}>
-            {p}
+            {p}{isLocked ? ' 🔒' : ''}
           </button>
-        ))}
+          )
+        })}
       </div>
 
       <div style={{ display: 'flex', gap: '0.35rem', marginBottom: '0.5rem' }}>