Claude Code just let you rewrite Claude Code

Create a mod called fin-dash: a financial analysis dashboard that opens in a side pane with /fin.

WHO AND WHICH DECISION
It is for [the founder] deciding each [month] [whether we can afford the next hire, which costs to cut, and which invoices to chase].

DATA
Read:
- [./data/ledger.csv]: date, type (income | expense), category, amount, counterparty
- [./data/invoices.csv]: invoice_id, client, issued, due, amount, paid_on (blank if unpaid)
- [./data/plan.json]: {"opening_cash": 2500000, "budget": {"<category>": <monthly amount>, ...}}
Currency [INR]. Re-read on /fin refresh and every [hour].

METRICS (by calendar month, last [6] months)
- Revenue = sum of income; Expenses = sum of expense
- Gross margin = (revenue − [cost of delivery categories: freelancers, software for clients]) / revenue
- Net burn = expenses − revenue (show as "net positive" when revenue is higher)
- Cash now = opening_cash + all income − all expenses to date
- Runway months = cash now / average net burn of the last [3] months
- Budget variance per category = actual − budget, and %
- Receivables: unpaid invoices bucketed by days past due: current, 1–30, 31–60, 60+
- Days sales outstanding = average days from issued to paid_on, last [90] days

LAYOUT (top to bottom)
1. Tiles: Cash now, Runway (months), Net burn this month, Gross margin %, Overdue receivables.
2. A 6-month chart of revenue against expenses, two block-character bars per month.
3. A table of expense categories: this month, budget, variance, 6-month sparkline. Sorted by variance, worst first.
4. Receivables ageing: one row per bucket with total and count, then the [5] largest overdue invoices with client and days late.
5. "What changed": the three categories with the biggest month-on-month change in money.

THRESHOLDS
- Runway below [12] months: amber; below [6]: red.
- A category over budget by more than [15%]: amber; [30%]: red.
- An invoice more than [30] days past due: amber; [60]: red.
- Gross margin down more than [5 points] month on month: amber.

INTERACTION
/fin opens or closes. /fin [category] shows that category's transactions for the month. /fin chase lists overdue invoices with client and amount. /fin month [YYYY-MM] moves the view.

ONE-LINE READ (optional)
One sentence from the model on the biggest risk to runway this month, from computed numbers only. Mark it "AI read — not financial advice".

GUARDRAILS
Read-only. It never sends reminders, moves money or edits the ledger.
Uncategorised rows are counted under "uncategorised" and shown as a warning, never spread across categories.
Every figure on the pane comes from the files; nothing is forecast unless I add a forecast section.
Write a test with fixture files that checks runway, budget variance and the receivable buckets.