QuillBot

Build me a local paraphrasing and grammar tool to replace QuillBot. Requirements: - A local web page on localhost:5170: Node + Express, one textarea in, one output pane, buttons for Paraphrase, Summarize, Fix grammar, and a tone select (standard, formal, casual, shorter). - Paraphrase, summarize, and tone modes call an LLM (Anthropic or OpenAI key in .env) with a fixed prompt per mode; stream the output. - Grammar mode calls a local LanguageTool server and lists each issue with its suggested fix, click to apply. No LLM needed for grammar. - A diff view between input and output with word-level highlights (the `diff` npm package). - Every run saved to SQLite via better-sqlite3: timestamp, mode, input, output. A history page lists the last 100 with copy buttons. - Cmd+Enter runs the selected mode. - No accounts, no telemetry; text leaves my machine only for LLM calls, grammar checking stays fully local. - Out of scope: browser and Word extensions, plagiarism and AI detection. This lives in one tab. - README: LanguageTool setup (needs Java or Docker) and which API key to add.