fix: resolve circular import, analysis API, locale mixing, and UX bugs

- Extract limiter to extensions.py to break circular import between app.py and blueprints
- Fix generate_study_explanation calling .get() on raw Response (needs .json() first)
- Pass locale parameter through /analyze and learning quiz fallback
- Change /uploads/<filename> from require_auth to optional_auth for <img> tags
- Prevent learn card collapse when selecting text or clicking inside expanded content

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app.py

@@ -4,14 +4,7 @@ import logging
 import torch
 from flask import Flask, jsonify
 from flask_cors import CORS
-from flask_limiter import Limiter
-from flask_limiter.util import get_remote_address
-
-limiter = Limiter(
-    get_remote_address,
-    default_limits=["60 per minute"],
-    storage_uri="memory://",
-)
+from extensions import limiter
 from dotenv import load_dotenv
 from src.dental_ontology import DentalOntology
 from src.claude_integration import ClaudeAssistant

blueprints/analysis.py

@@ -17,8 +17,8 @@ from flask import (
 from werkzeug.utils import secure_filename
 from PIL import Image, ImageDraw, ImageFont
 
-from app import limiter
-from src.auth import require_auth
+from extensions import limiter
+from src.auth import require_auth, optional_auth
 from src.analysis_helpers import allowed_file, ALLOWED_EXTENSIONS, normalize_image_orientation
 from src.analysis_service import _run_analysis
 from src.image_processing import (
@@ -65,7 +65,7 @@ def index():
 # ---------------------------------------------------------------------------
 
 @analysis_bp.route('/uploads/<filename>')
-@require_auth
+@optional_auth
 def uploaded_file(filename):
     filename = secure_filename(filename)
     if not filename:
@@ -100,7 +100,8 @@ def analyze():
     normalize_image_orientation(file_path)
 
     try:
-        result = _run_analysis(file_path, filename, False)
+        locale = request.form.get('locale', 'en')
+        result = _run_analysis(file_path, filename, False, locale=locale)
         _save_analysis_to_firestore(
             current_app.extensions.get('firestore'),
             g.user['clerk_id'], filename, result,

blueprints/learning.py

@@ -6,7 +6,7 @@ import random
 from flask import Blueprint, jsonify, request, current_app, g, send_from_directory, abort
 from werkzeug.utils import secure_filename
 
-from app import limiter
+from extensions import limiter
 from src.auth import optional_auth
 
 learning_bp = Blueprint('learning', __name__, url_prefix='/learn')
@@ -137,7 +137,7 @@ def check_quiz_answer():
             logger.info('Quiz check: no cached predictions, running analysis for %s', filename)
             try:
                 from src.analysis_service import _run_analysis
-                result = _run_analysis(image_path, filename, use_vision=False)
+                result = _run_analysis(image_path, filename, use_vision=False, locale=locale)
                 predictions = result.get('predictions', [])
                 # Cache the predictions for future quiz use
                 with open(predictions_path, 'w') as f:

extensions.py

@@ -0,0 +1,8 @@
+from flask_limiter import Limiter
+from flask_limiter.util import get_remote_address
+
+limiter = Limiter(
+    get_remote_address,
+    default_limits=["60 per minute"],
+    storage_uri="memory://",
+)

src/claude_integration.py

@@ -466,7 +466,11 @@ Return ONLY the JSON object, no additional text."""
                 "system": system_msg,
                 "messages": [{"role": "user", "content": user_msg}],
             }
-            result = self._api_request(data, timeout=30)
+            response = self._api_request(data, timeout=30)
+            if response.status_code != 200:
+                logger.error("Study explanation API error: %s %s", response.status_code, response.text[:200])
+                return None
+            result = response.json()
             content = result.get("content", [])
             if not content:
                 return None

static/js/learning.js

@@ -364,7 +364,12 @@ export async function initLearnBrowser() {
                     <p class="learn-card-preview">${cond.definition?.substring(0, 100) || ''}...</p>
                 `;
 
-                card.addEventListener('click', () => expandLearnCard(card, cond.key, locale));
+                card.addEventListener('click', (e) => {
+                    // Don't toggle if user is selecting text or clicked inside expanded content
+                    if (window.getSelection().toString()) return;
+                    if (card.classList.contains('expanded') && e.target.closest('.learn-card-content')) return;
+                    expandLearnCard(card, cond.key, locale);
+                });
                 grid.appendChild(card);
             }