feat: replace manual web scraping with an agentic tool-selection engine

refactor: replace agent-based web search with parallelized retrieval using Wikipedia and DuckDuckGo

feat: increase quiz generation capacity with dedicated high-token LLM.

feat: add religious, political and NSFW topics in prohibited content criteria in quiz and summary generators

refactor: update system prompts safety guidelines

feat: introduce robust web-based prompt templates for quizzes and summaries.

refactor: update content limits for quiz and summary generation modules

refactor: changing to gemini model, modularize constants and schemas and update user daily generation limit