feat(banking A): bank accounts module + finance integration

First of 3-step banking expansion. Banks tracked separately from
customer/supplier debts so we can compute real cash position later.

Schema:
- New bank_accounts table: bankName, accountName, iban, openingBalance,
  notes, archived. Indexes on (tenantId, archived).
- New column finance_entries.bankAccountId (FK, optional). Index on
  (tenantId, bankAccountId).
- schema.ts: TABLES.bankAccounts, BankAccount type, FinanceEntry gains
  bankAccountId.

Server side:
- lib/validation/bank-accounts.ts (Zod): IBAN normalized to upper-case
  no-spaces; openingBalance defaults to 0.
- lib/appwrite/bank-account-actions.ts: create/update/archive(toggle)/
  delete with audit. Delete refuses if any finance_entry still references
  the account; archive toggle replaces it for safe disable.
- lib/appwrite/bank-account-queries.ts:
  * listBankAccounts
  * getBankAccountBalances — computes opening + Σ(income) − Σ(expense)
    per account by scanning up to 5000 entries with bankAccountId set.
    Pure cash flow; debt/receivable don't move balance.
  * listEntriesForAccount

UI:
- /finance/banks server page renders BanksClient with computed balances.
- BanksClient: card grid for active accounts, collapsed details for
  archived. Sum card on top showing total active balance (color-coded by
  sign). Each card shows bank, account name, formatted IBAN, current
  balance + opening (if drifted). Dropdown: Düzenle / Arşivle / Sil.
- BankFormSheet: bank/account/IBAN/openingBalance/notes form.
- Finance form gets a bank-account Select (sentinel-stripped). Existing
  finance entries get a 'bankAccountLabel' subtitle in their row.

Sidebar: Finans group expanded with Bankalar submenu (Banka hesapları
/ Krediler / Kredi kartları). The latter two land in B and C.

src/lib/appwrite/bank-account-queries.ts

@@ -0,0 +1,93 @@
+import "server-only";
+
+import { Query } from "node-appwrite";
+
+import { createAdminClient } from "./server";
+import {
+  DATABASE_ID,
+  TABLES,
+  type BankAccount,
+  type FinanceEntry,
+} from "./schema";
+
+export async function listBankAccounts(tenantId: string): Promise<BankAccount[]> {
+  try {
+    const { tablesDB } = createAdminClient();
+    const result = await tablesDB.listRows({
+      databaseId: DATABASE_ID,
+      tableId: TABLES.bankAccounts,
+      queries: [
+        Query.equal("tenantId", tenantId),
+        Query.orderAsc("bankName"),
+        Query.limit(200),
+      ],
+    });
+    return result.rows as unknown as BankAccount[];
+  } catch {
+    return [];
+  }
+}
+
+/**
+ * Computes a current balance for each account: openingBalance + Σ(income/receivable) − Σ(expense/debt).
+ */
+export async function getBankAccountBalances(
+  tenantId: string,
+): Promise<Map<string, number>> {
+  const balances = new Map<string, number>();
+  try {
+    const { tablesDB } = createAdminClient();
+    const accounts = await tablesDB.listRows({
+      databaseId: DATABASE_ID,
+      tableId: TABLES.bankAccounts,
+      queries: [Query.equal("tenantId", tenantId), Query.limit(200)],
+    });
+    for (const a of accounts.rows as unknown as BankAccount[]) {
+      balances.set(a.$id, a.openingBalance ?? 0);
+    }
+
+    const entries = await tablesDB.listRows({
+      databaseId: DATABASE_ID,
+      tableId: TABLES.financeEntries,
+      queries: [
+        Query.equal("tenantId", tenantId),
+        Query.isNotNull("bankAccountId"),
+        Query.limit(5000),
+      ],
+    });
+    for (const e of entries.rows as unknown as FinanceEntry[]) {
+      if (!e.bankAccountId) continue;
+      const cur = balances.get(e.bankAccountId);
+      if (cur === undefined) continue;
+      if (e.type === "income") balances.set(e.bankAccountId, cur + e.amount);
+      else if (e.type === "expense") balances.set(e.bankAccountId, cur - e.amount);
+      // debt/receivable don't affect cash balance
+    }
+  } catch {
+    /* ignore */
+  }
+  return balances;
+}
+
+export async function listEntriesForAccount(
+  tenantId: string,
+  bankAccountId: string,
+  limit = 25,
+): Promise<FinanceEntry[]> {
+  try {
+    const { tablesDB } = createAdminClient();
+    const result = await tablesDB.listRows({
+      databaseId: DATABASE_ID,
+      tableId: TABLES.financeEntries,
+      queries: [
+        Query.equal("tenantId", tenantId),
+        Query.equal("bankAccountId", bankAccountId),
+        Query.orderDesc("date"),
+        Query.limit(limit),
+      ],
+    });
+    return result.rows as unknown as FinanceEntry[];
+  } catch {
+    return [];
+  }
+}