refactor(api): split views_api.py into a package of domain modules

Pure move — no logic changes. The 4,100-line single file becomes
views_api/ with one module per domain (accounts, entries, payments,
settings_reports, reconciliation, permissions, admin), each
registering full literal paths on its own APIRouter; __init__ builds
the combined libra_api_router so libra/__init__.py is untouched.
Shared imports/helpers live in views_api/_shared.py;
_extract_entry_id and _SYSTEM_LINK_PREFIXES move to
beancount_format.py (they are pure entry-dict parsing).

Route behavior is pinned by tests/test_route_table.py: the 73-route
set is unchanged, and the two order-sensitive families (the shadowed
/accounts/hierarchy wart — deliberately preserved here, fixed in the
next commit — and the admin sync literal/param pair) keep their
relative order inside a single module each.

Addresses CODE-REVIEW-2026-06 structure findings (views_api monolith).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

views_api/_shared.py

@@ -0,0 +1,177 @@
+"""Shared imports and helpers for the views_api package.
+
+Everything module-level that the pre-split views_api.py defined above
+its first route lives here; endpoint modules pull it in with a
+wildcard import plus explicit imports for underscore-prefixed names
+(which `import *` does not export).
+"""
+from datetime import datetime
+from decimal import Decimal
+from http import HTTPStatus
+from typing import Optional
+
+from fastapi import APIRouter, Depends, HTTPException
+from loguru import logger
+from lnbits.core.models import User, WalletTypeInfo
+from lnbits.decorators import (
+    check_super_user,
+    check_user_exists,
+    require_invoice_key,
+)
+from lnbits.utils.exchange_rates import allowed_currencies, fiat_amount_as_satoshis
+
+from ..account_utils import VALID_ACCOUNT_PREFIXES, validate_account_name
+from ..beancount_format import (
+    _SYSTEM_LINK_PREFIXES,
+    _extract_entry_id,
+    fiat_rate_metadata,
+)
+from ..user_lookup import get_username
+from ..crud import (
+    approve_manual_payment_request,
+    check_balance_assertion,
+    create_account,
+    create_account_permission,
+    create_balance_assertion,
+    create_manual_payment_request,
+    db,
+    delete_account_permission,
+    delete_balance_assertion,
+    get_account,
+    get_account_by_name,
+    get_account_permission,
+    get_account_permissions,
+    get_all_accounts,
+    get_all_manual_payment_requests,
+    get_all_user_wallet_settings,
+    get_balance_assertion,
+    get_balance_assertions,
+    get_manual_payment_request,
+    get_or_create_user_account,
+    get_user_manual_payment_requests,
+    get_user_permissions,
+    get_user_permissions_with_inheritance,
+    reject_manual_payment_request,
+)
+from ..models import (
+    Account,
+    AccountPermission,
+    AccountType,
+    AccountWithPermissions,
+    AssertionStatus,
+    AssignUserRole,
+    BalanceAssertion,
+    BulkGrantPermission,
+    BulkGrantResult,
+    LibraSettings,
+    CreateAccount,
+    CreateAccountPermission,
+    CreateChartAccount,
+    CreateBalanceAssertion,
+    CreateEntryLine,
+    CreateJournalEntry,
+    CreateManualPaymentRequest,
+    CreateRole,
+    CreateRolePermission,
+    CreateUserEquityStatus,
+    ExpenseEntry,
+    GeneratePaymentInvoice,
+    IncomeEntry,
+    JournalEntry,
+    JournalEntryFlag,
+    ManualPaymentRequest,
+    PayUser,
+    PermissionType,
+    ReceivableEntry,
+    RecordPayment,
+    RevenueEntry,
+    Role,
+    RolePermission,
+    RoleWithPermissions,
+    SettleReceivable,
+    UpdateRole,
+    UserBalance,
+    UserEquityStatus,
+    UserInfo,
+    UserRole,
+    UserWalletSettings,
+    UserWithRoles,
+)
+from ..services import get_settings, get_user_wallet, update_settings, update_user_wallet
+from ..auth import (
+    AuthContext,
+    require_authenticated,
+    require_authenticated_write,
+    require_super_user,
+    require_account_access,
+    require_user_data_access,
+)
+
+
+# Synthetic Beancount flags marking auto-generated entries (summarization,
+# padding, transfers, conversions, unrealized gains, returns, merging) that
+# should not appear in user-facing transaction lists. Mirrors Fava's
+# _EXCL_FLAGS in fava/core/file.py.
+_SYNTHETIC_FLAGS = frozenset({"S", "T", "C", "P", "U", "R", "M"})
+
+
+# ===== HELPER FUNCTIONS =====
+
+
+async def check_libra_wallet_configured() -> str:
+    """Ensure libra wallet is configured, return wallet_id"""
+    settings = await get_settings("admin")
+    if not settings or not settings.libra_wallet_id:
+        raise HTTPException(
+            status_code=HTTPStatus.BAD_REQUEST,
+            detail="Libra wallet not configured. Please contact the super user to configure the Libra wallet in settings.",
+        )
+    return settings.libra_wallet_id
+
+
+async def check_user_wallet_configured(user_id: str) -> str:
+    """Ensure user has configured their wallet, return wallet_id"""
+    from lnbits.settings import settings as lnbits_settings
+
+    # If user is super user, use the libra wallet
+    if user_id == lnbits_settings.super_user:
+        libra_settings = await get_settings("admin")
+        if libra_settings and libra_settings.libra_wallet_id:
+            return libra_settings.libra_wallet_id
+        raise HTTPException(
+            status_code=HTTPStatus.BAD_REQUEST,
+            detail="Libra wallet not configured. Please configure the Libra wallet in settings.",
+        )
+
+    # For regular users, check their personal wallet
+    user_wallet = await get_user_wallet(user_id)
+    if not user_wallet or not user_wallet.user_wallet_id:
+        raise HTTPException(
+            status_code=HTTPStatus.BAD_REQUEST,
+            detail="You must configure your wallet in settings before using this feature.",
+        )
+    return user_wallet.user_wallet_id
+
+
+# ===== UTILITY ENDPOINTS =====
+
+
+
+_VALID_ACCOUNT_PREFIXES = VALID_ACCOUNT_PREFIXES
+
+
+def _validate_account_name(name: str) -> None:
+    """Raise HTTP 400 if ``name`` is not a syntactically valid Beancount account.
+
+    Thin HTTP wrapper around account_utils.validate_account_name — the
+    single source of truth for account-name syntax (libra-#51).
+    """
+    try:
+        validate_account_name(name)
+    except ValueError as e:
+        raise HTTPException(
+            status_code=HTTPStatus.BAD_REQUEST,
+            detail=str(e),
+        )
+
+