Initial commit: MyMidas personal finance tracker

Full-stack self-hosted finance app with FastAPI backend and React frontend.

Features:
- Accounts, transactions, budgets, investments with GBP base currency
- CSV import with auto-detection for 10 UK bank formats
- ML predictions: spending forecast, net worth projection, Monte Carlo
- 7 selectable themes (Obsidian, Arctic, Midnight, Vault, Terminal, Synthwave, Ledger)
- Receipt/document attachments on transactions (JPEG, PNG, WebP, PDF)
- AES-256-GCM field encryption, RS256 JWT, TOTP 2FA, RLS, audit log
- Encrypted nightly backups + key rotation script
- Mobile-responsive layout with bottom nav

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/api/predictions.ts

@@ -0,0 +1,109 @@
+import { api } from "./client";
+
+export interface CategoryForecast {
+  category_id: string;
+  category_name: string;
+  monthly_avg: number;
+  actuals: { date: string; amount: number }[];
+  forecast: { date: string; amount: number; lower: number; upper: number }[];
+}
+
+export interface SpendingForecastResponse {
+  categories: CategoryForecast[];
+}
+
+export interface NetWorthProjectionResponse {
+  history: { date: string; value: number }[];
+  projections: {
+    conservative: { date: string; value: number }[];
+    base: { date: string; value: number }[];
+    optimistic: { date: string; value: number }[];
+  };
+  insufficient_data: boolean;
+}
+
+export interface PercentilePath {
+  date: string;
+  value: number;
+}
+
+export interface MonteCarloResponse {
+  dates: string[];
+  percentiles: {
+    p10: PercentilePath[];
+    p25: PercentilePath[];
+    p50: PercentilePath[];
+    p75: PercentilePath[];
+    p90: PercentilePath[];
+  };
+  current_value: number;
+  expected_value: number;
+  probability_of_gain: number;
+  insufficient_data: boolean;
+}
+
+export interface BudgetForecastItem {
+  category_id: string;
+  category_name: string;
+  budget_amount: number;
+  spent_so_far: number;
+  forecast_month_total: number;
+  daily_velocity: number;
+  probability_overspend: number;
+  days_remaining: number;
+}
+
+export interface BudgetForecastResponse {
+  forecasts: BudgetForecastItem[];
+  message?: string;
+}
+
+export interface CashFlowDay {
+  date: string;
+  balance: number;
+  avg_inflow: number;
+  avg_outflow: number;
+  negative_risk: boolean;
+}
+
+export interface CashFlowResponse {
+  current_balance: number;
+  avg_daily_inflow: number;
+  avg_daily_outflow: number;
+  forecast: CashFlowDay[];
+  negative_risk_days: string[];
+  history_days: number;
+}
+
+export async function getSpendingForecast(): Promise<SpendingForecastResponse> {
+  const res = await api.get("/predictions/spending");
+  return res.data;
+}
+
+export async function getNetWorthProjection(years = 5): Promise<NetWorthProjectionResponse> {
+  const res = await api.get("/predictions/net-worth", { params: { years } });
+  return res.data;
+}
+
+export async function postMonteCarlo(params: {
+  years?: number;
+  n_simulations?: number;
+  annual_contribution?: number;
+}): Promise<MonteCarloResponse> {
+  const res = await api.post("/predictions/monte-carlo", {
+    years: params.years ?? 5,
+    n_simulations: params.n_simulations ?? 1000,
+    annual_contribution: params.annual_contribution ?? 0,
+  });
+  return res.data;
+}
+
+export async function getBudgetForecast(): Promise<BudgetForecastResponse> {
+  const res = await api.get("/predictions/budget-forecast");
+  return res.data;
+}
+
+export async function getCashFlowForecast(): Promise<CashFlowResponse> {
+  const res = await api.get("/predictions/cashflow");
+  return res.data;
+}