Lohnt sich dein eigenes Coda?

Build me a docs-with-tables workspace to replace Coda, single-user.
Requirements:

- Local web app: Node + Express + better-sqlite3, server-rendered pages with
  vanilla JS, no build step.
- Docs are Markdown edited in a textarea with live preview (marked); a
  fenced block naming a table, like table:Expenses, renders that table live
  inside the doc.
- Tables have typed columns (text/number/date/select/checkbox), inline row
  editing, and are real SQLite tables I can query with other tools.
- Formula columns: a JS expression over the row's other fields (price * qty)
  evaluated server-side with new Function over plain values only, recomputed
  on edit. No imports, no network access in formulas.
- Buttons in docs: a doc can declare a button that runs one whitelisted
  server action (add row with defaults, mark done); docs never execute
  arbitrary code.
- Named views per table: filter + sort saved and embeddable in any doc.
- CSV export per table, Markdown export per doc; localhost only, no
  accounts, no telemetry.
- Out of scope: collaboration, permissions, and packs/integrations. Coda's
  formula language and pack ecosystem are the product; this is my personal
  version.
- README: setup and where the data lives on disk.