Build a complete, polished local-first web app called "Lab Notes" for people who run AI experiments and want to write them down honestly: what they tried, what worked, and what didn't. Use Vite + TypeScript with no backend, no accounts, no paid services and no API keys. All data stays in the browser (IndexedDB).

Features:
1. Experiments: create, edit, duplicate and delete an experiment with a title, goal, tool/model used, date, tags, status (planned / running / worked / partly worked / failed), and a free-text "what I learned".
2. Runs inside each experiment: every run stores the exact prompt, the input, the output (text), optional images (drag and drop or paste from clipboard, stored locally), time spent, cost, and a pass/fail note. Show a side-by-side diff between the prompts of any two runs.
3. A dashboard with search, tag and status filters, and small charts drawn without a chart library: experiments per week, worked vs failed ratio, and total time and cost.
4. Export any experiment as a clean Markdown case study (with images in a ZIP you build yourself in the browser, no zip library) and as a printable page. Import and export the whole database as JSON so nothing is locked in.
5. Keyboard shortcuts (new experiment, new run, search, save) with a visible shortcut sheet.
6. Fully responsive for phone and desktop, accessible (labels, focus states, contrast), light and dark mode, and it must feel fast with 500 experiments: generate a demo-data button to prove it.
7. Write unit tests (Vitest) for the data layer, the diff, the ZIP writer and the Markdown export, and make them pass. Run `npm run build` and `npm test` at the end and fix every error until both pass. Do not start a dev server and do not deploy anything.
8. Finish with a README.md that honestly lists what works, what you simplified, and known limitations.