Local-first, single-user personal budgeting app. Import CSVs from Star One Credit Union (checking + savings), categorize, and track envelope-style budgets — without handing your transactions to Plaid or a cloud service.

Status: Weekend 1 complete. Import pipeline works end-to-end (parse → dedup → snapshot → transactional insert → transfer-pair linking). See PLAN.md and CHANGELOG.md.

• Next.js 16 (App Router + Turbopack) · React 19 · TypeScript
• Tailwind v4 · shadcn/ui (base-nova style, Base UI primitives)
• better-sqlite3 + Drizzle ORM — local SQLite file at ./data/money.db
• Vitest for parser/categorization unit tests
• pnpm · Node 24 (pinned via .nvmrc)

No cloud. No auth. No Plaid. No deployment target — this runs on your machine.

nvm use                 # picks up Node 24 from .nvmrc
pnpm install
pnpm db:migrate         # applies Drizzle migrations to ./data/money.db
pnpm dev                # http://localhost:3000 → redirects to /import

Create an account (name, type, starting balance + date) from /import, then upload a Star One CSV export. The preview shows row counts, duplicates, pending rows, and errors; clicking Confirm import snapshots the DB, inserts the batch inside a transaction, and links transfer pairs across accounts.

src/
  app/        Next.js 16 App Router pages (/import, /import/preview/[id], /import/success/[batchId])
  components/ shadcn/ui + app components
  db/         Drizzle schema + HMR-safe client singleton
  lib/        parseCsv, normalize, hash, transferPair, snapshot, importBatch, pendingImport
drizzle/      Committed migration output
data/         money.db, pre-import snapshots, pending-import stash (gitignored)
.context/     Design artifacts, CSV samples, design deltas (gitignored)

These are load-bearing — the whole app is built around them:

1. All money is stored as signed integer amount_cents. Never floats. Withdrawals negative, deposits positive.
2. The CSV's signs are already correct. Amount Debit is pre-negative, Amount Credit is positive. No Math.abs, no sign flips by description. (This is the bug Plaid users keep hitting.)
3. Dedup is (account_id, import_batch_id, import_row_hash), never Star One's Transaction Number — they reuse 6098 for pending deposits across rows. import_row_hash = sha1(date | amount_cents | raw_description | raw_memo | row_index).
4. Transfer-pair detection is memo-independent. Two rows pair iff |txn_a - txn_b| == 1 AND same date AND |amount_a| == |amount_b| AND opposite signs AND different accounts. Star One labels the receiving-side memo correctly only ~20% of the time, so memo is confirmation-only.
5. Every batch import writes a DB snapshot first to data/money.db.pre-import-{timestamp}. Last 10 are kept. Rollback = stop dev server, swap file.

Credit cards. Auth. Cloud sync. Multi-currency. Bill pay. Investment tracking. Tax features. Split transactions. YNAB-style overspend-shuffle. CI. Deployment.

• CLAUDE.md — guide for AI agents working in this repo (rules, conventions, Next.js 16 gotchas)
• PLAN.md — 5-weekend roadmap
• TODOS.md — short-term checklist
• CHANGELOG.md — release notes