fix: make docker compose build and start the API

The image context was backend/, so COPY frontend/ failed. Build from the
repo root, place Python modules on the import path, and pin packages that
exist on PyPI. The web process no longer loads the LLM at startup.

backend/app/tasks/celery_tasks.py

@@ -0,0 +1,73 @@
+from celery import Celery
+from celery.schedules import crontab
+from app.services.bot_service import BotService
+import os
+import json
+from datetime import datetime, timedelta
+from typing import List, Dict, Optional
+
+celery = Celery(
+    'tasks',
+    broker=os.getenv("CELERY_BROKER_URL", "redis://localhost:6379/0"),
+    backend=os.getenv("CELERY_RESULT_BACKEND", "redis://localhost:6379/0"),
+)
+
+bot_service = BotService(
+    os.getenv("TELEGRAM_BOT_TOKEN", ""),
+    os.getenv("TELEGRAM_CHAT_ID", "")
+)
+
+# Load schedules from JSON
+def load_schedules() -> List[Dict]:
+    schedules_path = "/app/schedules.json"
+    if os.path.exists(schedules_path):
+        with open(schedules_path, "r") as f:
+            return json.load(f)
+    return []
+
+# Save schedules to JSON
+def save_schedules(schedules: List[Dict]):
+    with open("/app/schedules.json", "w") as f:
+        json.dump(schedules, f, indent=2)
+
+@celery.task
+def send_scheduled_message(schedule_id: int = None):
+    """Send one schedule, or every enabled schedule when id is omitted."""
+    schedules = load_schedules()
+    if schedule_id is None:
+        selected = [item for item in schedules if item.get("enabled", True)]
+    else:
+        selected = [item for item in schedules if item.get("id") == schedule_id and item.get("enabled", True)]
+
+    if not selected:
+        print(f"Schedule {schedule_id} not found")
+        return
+
+    for schedule in selected:
+        try:
+            bot_service.send_scheduled_message(schedule)
+            print(f"Sent scheduled message: {schedule['time']}")
+        except Exception as e:
+            print(f"Error sending scheduled message: {e}")
+
+@celery.task
+def generate_daily_content():
+    """Generate daily content for all books."""
+    try:
+        bot_service.generate_daily_content()
+        print("Sent daily content")
+    except Exception as e:
+        print(f"Error generating daily content: {e}")
+
+# Periodic tasks
+celery.conf.beat_schedule = {
+    'send-scheduled-messages': {
+        'task': 'app.tasks.celery_tasks.send_scheduled_message',
+        'schedule': crontab(minute=0),  # Every hour
+        'args': (None,),  # Process all enabled schedules
+    },
+    'generate-daily-content': {
+        'task': 'app.tasks.celery_tasks.generate_daily_content',
+        'schedule': crontab(hour=8, minute=0),  # Daily at 8 AM
+    },
+}