feat: multi-account Fio sync + switch QR default to 2502035405/2010

Add second Fio account (CZ0820100000002502035405 / 2502035405/2010).
Both accounts are fetched on every sync run and combined before dedup,
so the payments sheet accumulates transactions from either account.
QR codes now default to the new account.

Go:
- config.go: hardcoded Accounts/LoadedAccount slice replaces scalar
  BankAccount + FioAPIToken; Config.BankAccount renamed QRAccount;
  per-account tokens via FIO_API_TOKEN_NEW / FIO_API_TOKEN_OLD
- banksync.SyncToSheets: accepts []fio.Client, loops to combine txns
- cmd/fuj/main.go: buildFioClients helper; both sync call sites updated
- html_handler + build_adults/juniors: use Config.QRAccount
- New TestSyncToSheets_MultiAccount covers cross-account dedup

Python:
- config.py: ACCOUNTS list + LOADED_ACCOUNTS (tokens from env)
- fio_utils.py: fetch_transactions_for (per-account) +
  fetch_transactions_all (loops all accounts)
- sync_fio_to_sheets.py: uses fetch_transactions_all

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

go/internal/config/config.go

@@ -7,6 +7,28 @@ import (
 	"time"
 )
 
+// Account describes a Fio bank account.
+type Account struct {
+	IBAN     string // e.g. "CZ0820100000002502035405"
+	AcctNum  string // bare account number, e.g. "2502035405"
+	TokenEnv string // env var name holding the optional Fio API token
+	Primary  bool   // true for the account QR codes default to
+}
+
+// LoadedAccount is an Account with its token resolved from the environment.
+type LoadedAccount struct {
+	Account
+	Token string // value of os.Getenv(Account.TokenEnv); empty → transparent-scraper path
+}
+
+// Accounts is the hardcoded list of Fio bank accounts to sync from.
+// The first entry with Primary=true is used for QR codes.
+// Tokens are loaded at runtime from each account's TokenEnv.
+var Accounts = []Account{
+	{IBAN: "CZ0820100000002502035405", AcctNum: "2502035405", TokenEnv: "FIO_API_TOKEN_NEW", Primary: true},
+	{IBAN: "CZ8520100000002800359168", AcctNum: "2800359168", TokenEnv: "FIO_API_TOKEN_OLD"},
+}
+
 // Google Sheets IDs — change in code if sheets change (not from env).
 const (
 	AttendanceSheetID = "1E2e_gT_K5AwSRCDLDTa2UetZTkHmBOcz0kFbBUNUNBA"
@@ -34,28 +56,36 @@ var CacheSheetMap = map[string]string{
 // Mirrors scripts/config.py.
 type Config struct {
 	CredentialsPath  string
-	BankAccount      string
+	QRAccount        string          // IBAN of the primary account used for QR codes
+	LoadedAccounts   []LoadedAccount // all accounts to sync, tokens resolved from env
 	CacheDir         string
 	CacheTTL         time.Duration
 	CacheAPICheckTTL time.Duration
 	DriveTimeout     time.Duration
 	LogLevel         string
-	FioAPIToken      string
 	ServerAddr       string
 }
 
 // Load reads configuration from the environment, applying defaults that
 // match the Python side.
 func Load() Config {
+	loaded := make([]LoadedAccount, len(Accounts))
+	var qrAccount string
+	for i, a := range Accounts {
+		loaded[i] = LoadedAccount{Account: a, Token: os.Getenv(a.TokenEnv)}
+		if a.Primary {
+			qrAccount = a.IBAN
+		}
+	}
 	return Config{
 		CredentialsPath:  env("CREDENTIALS_PATH", ".secret/fuj-management-bot-credentials.json"),
-		BankAccount:      env("BANK_ACCOUNT", "CZ8520100000002800359168"),
+		QRAccount:        qrAccount,
+		LoadedAccounts:   loaded,
 		CacheDir:         env("CACHE_DIR", "tmp/go"),
 		CacheTTL:         envDuration("CACHE_TTL_SECONDS", 300),
 		CacheAPICheckTTL: envDuration("CACHE_API_CHECK_TTL_SECONDS", 300),
 		DriveTimeout:     envDuration("DRIVE_TIMEOUT_SECONDS", 10),
 		LogLevel:         env("LOG_LEVEL", "INFO"),
-		FioAPIToken:      env("FIO_API_TOKEN", ""),
 		ServerAddr:       env("SERVER_ADDR", ":8080"),
 	}
 }

go/internal/services/banksync/sync.go

@@ -35,13 +35,13 @@ type SyncOpts struct {
 	PrintFioTable bool      // with DryRun: print every fetched Fio txn with NEW/DUP status
 }
 
-// SyncToSheets fetches Fio transactions and appends new ones to the payments sheet.
-// Returns the number of rows appended.
+// SyncToSheets fetches Fio transactions from all provided clients and appends
+// new ones to the payments sheet. Returns the number of rows appended.
 // Ports scripts/sync_fio_to_sheets.py sync_to_sheets.
 func SyncToSheets(
 	ctx context.Context,
 	spreadsheetID string,
-	fioClient fio.Client,
+	fioClients []fio.Client,
 	sh sheetsWriter,
 	opts SyncOpts,
 ) (int, error) {
@@ -84,10 +84,14 @@ func SyncToSheets(
 		from = to.AddDate(0, 0, -days)
 	}
 
-	// 3. Fetch Fio transactions.
-	txns, err := fioClient.FetchTransactions(ctx, from, to)
-	if err != nil {
-		return 0, fmt.Errorf("sync: fetch fio: %w", err)
+	// 3. Fetch Fio transactions from each account and combine.
+	var txns []fio.Transaction
+	for _, client := range fioClients {
+		got, err := client.FetchTransactions(ctx, from, to)
+		if err != nil {
+			return 0, fmt.Errorf("sync: fetch fio: %w", err)
+		}
+		txns = append(txns, got...)
 	}
 	if opts.DryRun {
 		fmt.Printf("Dry run: window %s to %s, fetched %d transaction(s) from Fio\n",

go/internal/services/banksync/sync_test.go

@@ -20,7 +20,7 @@ func TestSyncToSheets_EmptySheet(t *testing.T) {
 	}}
 	fioFake := &fio.Fake{Transactions: testFioTxns}
 
-	n, err := SyncToSheets(context.Background(), "SHEETID", fioFake, sh, SyncOpts{Days: 30})
+	n, err := SyncToSheets(context.Background(), "SHEETID", []fio.Client{fioFake}, sh, SyncOpts{Days: 30})
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -51,7 +51,7 @@ func TestSyncToSheets_Dedup(t *testing.T) {
 	}}
 	fioFake := &fio.Fake{Transactions: testFioTxns}
 
-	n, err := SyncToSheets(context.Background(), "SHEETID", fioFake, sh, SyncOpts{Days: 30})
+	n, err := SyncToSheets(context.Background(), "SHEETID", []fio.Client{fioFake}, sh, SyncOpts{Days: 30})
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -72,7 +72,7 @@ func TestSyncToSheets_NoNewTxns(t *testing.T) {
 	}}
 	fioFake := &fio.Fake{Transactions: testFioTxns}
 
-	n, err := SyncToSheets(context.Background(), "SHEETID", fioFake, sh, SyncOpts{Days: 30})
+	n, err := SyncToSheets(context.Background(), "SHEETID", []fio.Client{fioFake}, sh, SyncOpts{Days: 30})
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -92,7 +92,7 @@ func TestSyncToSheets_MissingHeader(t *testing.T) {
 	}}
 	fioFake := &fio.Fake{Transactions: testFioTxns[:1]}
 
-	n, err := SyncToSheets(context.Background(), "SHEETID", fioFake, sh, SyncOpts{Days: 30})
+	n, err := SyncToSheets(context.Background(), "SHEETID", []fio.Client{fioFake}, sh, SyncOpts{Days: 30})
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -105,7 +105,7 @@ func TestSyncToSheets_Sort(t *testing.T) {
 	sh := &sheets.Fake{Values: map[string][][]any{"SHEETID/A1:K": {}}}
 	fioFake := &fio.Fake{Transactions: testFioTxns[:1]}
 
-	_, err := SyncToSheets(context.Background(), "SHEETID", fioFake, sh, SyncOpts{Days: 30, Sort: true})
+	_, err := SyncToSheets(context.Background(), "SHEETID", []fio.Client{fioFake}, sh, SyncOpts{Days: 30, Sort: true})
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -118,7 +118,7 @@ func TestSyncToSheets_ExplicitDateWindow(t *testing.T) {
 
 	from := time.Date(2026, 4, 1, 0, 0, 0, 0, time.UTC)
 	to := time.Date(2026, 4, 30, 0, 0, 0, 0, time.UTC)
-	n, err := SyncToSheets(context.Background(), "SHEETID", fioFake, sh, SyncOpts{From: from, To: to})
+	n, err := SyncToSheets(context.Background(), "SHEETID", []fio.Client{fioFake}, sh, SyncOpts{From: from, To: to})
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -131,7 +131,7 @@ func TestSyncToSheets_DryRun(t *testing.T) {
 	sh := &sheets.Fake{Values: map[string][][]any{"SHEETID/A1:K": {}}}
 	fioFake := &fio.Fake{Transactions: testFioTxns}
 
-	n, err := SyncToSheets(context.Background(), "SHEETID", fioFake, sh,
+	n, err := SyncToSheets(context.Background(), "SHEETID", []fio.Client{fioFake}, sh,
 		SyncOpts{Days: 30, Sort: true, DryRun: true})
 	if err != nil {
 		t.Fatal(err)
@@ -144,6 +144,40 @@ func TestSyncToSheets_DryRun(t *testing.T) {
 	}
 }
 
+func TestSyncToSheets_MultiAccount(t *testing.T) {
+	txnsA := []fio.Transaction{
+		{Date: "2026-04-10", Amount: 700, Sender: "Alice", Message: "april", VS: "1", BankID: "A1"},
+	}
+	txnsB := []fio.Transaction{
+		{Date: "2026-04-11", Amount: 500, Sender: "Bob", Message: "duben", VS: "2", BankID: "B1"},
+	}
+	// One transaction that duplicates the first one from account A (same sync_id).
+	dupID := syncIDFor(txnsA[0])
+	sh := &sheets.Fake{Values: map[string][][]any{
+		"SHEETID/A1:K": {
+			{"Date", "Amount", "manual fix", "Person", "Purpose", "Inferred Amount", "Sender", "VS", "Message", "Bank ID", "Sync ID"},
+			{"2026-04-10", 700.0, "", "", "", "", "Alice", "1", "april", "A1", dupID},
+		},
+	}}
+	fakeA := &fio.Fake{Transactions: txnsA}
+	fakeB := &fio.Fake{Transactions: txnsB}
+
+	n, err := SyncToSheets(context.Background(), "SHEETID", []fio.Client{fakeA, fakeB}, sh, SyncOpts{Days: 30})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if n != 1 {
+		t.Errorf("want 1 new row (B1 from account B; A1 is duplicate), got %d", n)
+	}
+	if len(sh.Appended) != 1 || len(sh.Appended[0].Rows) != 1 {
+		t.Fatalf("want exactly 1 row appended, got %v", sh.Appended)
+	}
+	row := sh.Appended[0].Rows[0]
+	if row[6] != "Bob" {
+		t.Errorf("expected Bob's row, got sender=%v", row[6])
+	}
+}
+
 // syncIDFor mirrors what SyncToSheets computes for a given fio.Transaction.
 func syncIDFor(tx fio.Transaction) string {
 	currency := tx.Currency

go/internal/web/api/build_adults.go

@@ -138,7 +138,7 @@ func buildAdultsResponse(
 		Unmatched:     unmatched,
 		AttendanceURL: "https://docs.google.com/spreadsheets/d/" + config.AttendanceSheetID + "/edit",
 		PaymentsURL:   "https://docs.google.com/spreadsheets/d/" + config.PaymentsSheetID + "/edit",
-		BankAccount:   cfg.BankAccount,
+		BankAccount:   cfg.QRAccount,
 		CurrentMonth:  currentMonth,
 	}
 }

go/internal/web/api/build_juniors.go

@@ -134,7 +134,7 @@ func buildJuniorsResponse(
 		Unmatched:     unmatched,
 		AttendanceURL: juniorURL,
 		PaymentsURL:   "https://docs.google.com/spreadsheets/d/" + config.PaymentsSheetID + "/edit",
-		BankAccount:   cfg.BankAccount,
+		BankAccount:   cfg.QRAccount,
 		CurrentMonth:  currentMonth,
 	}
 }

go/internal/web/html_handler.go

@@ -126,13 +126,13 @@ func (h *HTMLHandler) ServeQR(w http.ResponseWriter, r *http.Request) {
 	amount := q.Get("amount")
 	message := q.Get("message")
 	if account == "" {
-		account = h.apiHandler.Config.BankAccount
+		account = h.apiHandler.Config.QRAccount
 	}
 	if amount == "" {
 		amount = "0"
 	}
 
-	payload := BuildSPD(account, amount, message, h.apiHandler.Config.BankAccount)
+	payload := BuildSPD(account, amount, message, h.apiHandler.Config.QRAccount)
 	png, err := RenderQRCode(payload)
 	if err != nil {
 		http.Error(w, "qr encode: "+err.Error(), http.StatusInternalServerError)

go/internal/web/html_handler_test.go

@@ -50,7 +50,7 @@ func fixtureHandler(t *testing.T) *api.Handler {
 	t.Helper()
 	return &api.Handler{
 		Sources: fixtureSources{},
-		Config:  config.Config{BankAccount: "CZ0000000000000000000000"},
+		Config:  config.Config{QRAccount: "CZ0000000000000000000000"},
 	}
 }