feat: Transform to web architecture with FastAPI backend

This major update transforms leggen from CLI-only to a web-ready
architecture while maintaining full CLI compatibility.

New Features:
- FastAPI backend service (leggend) with comprehensive REST API
- Background job scheduler with configurable cron (replaces Ofelia)
- All CLI commands refactored to use API endpoints
- Docker configuration updated for new services
- API client with health checks and error handling

API Endpoints:
- /api/v1/banks/* - Bank connections and institutions
- /api/v1/accounts/* - Account management and balances
- /api/v1/transactions/* - Transaction retrieval with filtering
- /api/v1/sync/* - Manual sync and scheduler configuration
- /api/v1/notifications/* - Notification settings management

CLI Enhancements:
- New --api-url option and LEGGEND_API_URL environment variable
- Enhanced sync command with --wait and --force options
- Improved transactions command with --full and --limit options
- Automatic fallback and health checking

Breaking Changes:
- compose.yml structure updated (leggend service added)
- Ofelia scheduler removed (internal scheduler used instead)

🤖 Generated with [Claude Code](https://claude.ai/code)

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

leggend/api/models/accounts.py

@@ -0,0 +1,70 @@
+from datetime import datetime
+from typing import List, Optional, Dict, Any
+
+from pydantic import BaseModel
+
+
+class AccountBalance(BaseModel):
+    """Account balance model"""
+    amount: float
+    currency: str
+    balance_type: str
+    last_change_date: Optional[datetime] = None
+    
+    class Config:
+        json_encoders = {
+            datetime: lambda v: v.isoformat() if v else None
+        }
+
+
+class AccountDetails(BaseModel):
+    """Account details model"""
+    id: str
+    institution_id: str
+    status: str
+    iban: Optional[str] = None
+    name: Optional[str] = None
+    currency: Optional[str] = None
+    created: datetime
+    last_accessed: Optional[datetime] = None
+    balances: List[AccountBalance] = []
+    
+    class Config:
+        json_encoders = {
+            datetime: lambda v: v.isoformat() if v else None
+        }
+
+
+class Transaction(BaseModel):
+    """Transaction model"""
+    internal_transaction_id: str
+    institution_id: str
+    iban: Optional[str] = None
+    account_id: str
+    transaction_date: datetime
+    description: str
+    transaction_value: float
+    transaction_currency: str
+    transaction_status: str  # "booked" or "pending"
+    raw_transaction: Dict[str, Any]
+    
+    class Config:
+        json_encoders = {
+            datetime: lambda v: v.isoformat()
+        }
+
+
+class TransactionSummary(BaseModel):
+    """Transaction summary for lists"""
+    internal_transaction_id: str
+    date: datetime
+    description: str
+    amount: float
+    currency: str
+    status: str
+    account_id: str
+    
+    class Config:
+        json_encoders = {
+            datetime: lambda v: v.isoformat()
+        }

leggend/api/models/banks.py

@@ -0,0 +1,52 @@
+from datetime import datetime
+from typing import List, Optional
+
+from pydantic import BaseModel
+
+
+class BankInstitution(BaseModel):
+    """Bank institution model"""
+    id: str
+    name: str
+    bic: Optional[str] = None
+    transaction_total_days: int
+    countries: List[str]
+    logo: Optional[str] = None
+
+
+class BankConnectionRequest(BaseModel):
+    """Request to connect to a bank"""
+    institution_id: str
+    redirect_url: Optional[str] = "http://localhost:8000/"
+
+
+class BankRequisition(BaseModel):
+    """Bank requisition/connection model"""
+    id: str
+    institution_id: str
+    status: str
+    status_display: Optional[str] = None
+    created: datetime
+    link: str
+    accounts: List[str] = []
+    
+    class Config:
+        json_encoders = {
+            datetime: lambda v: v.isoformat()
+        }
+
+
+class BankConnectionStatus(BaseModel):
+    """Bank connection status response"""
+    bank_id: str
+    bank_name: str
+    status: str
+    status_display: str
+    created_at: datetime
+    requisition_id: str
+    accounts_count: int
+    
+    class Config:
+        json_encoders = {
+            datetime: lambda v: v.isoformat()
+        }

leggend/api/models/common.py

@@ -0,0 +1,27 @@
+from datetime import datetime
+from typing import Any, Dict, Optional
+
+from pydantic import BaseModel
+
+
+class APIResponse(BaseModel):
+    """Base API response model"""
+    success: bool = True
+    message: Optional[str] = None
+    data: Optional[Any] = None
+
+
+class ErrorResponse(BaseModel):
+    """Error response model"""
+    success: bool = False
+    message: str
+    error_code: Optional[str] = None
+    details: Optional[Dict[str, Any]] = None
+
+
+class PaginatedResponse(BaseModel):
+    """Paginated response model"""
+    success: bool = True
+    data: list
+    pagination: Dict[str, Any]
+    message: Optional[str] = None

leggend/api/models/notifications.py

@@ -0,0 +1,47 @@
+from typing import Dict, Any, Optional, List
+
+from pydantic import BaseModel
+
+
+class DiscordConfig(BaseModel):
+    """Discord notification configuration"""
+    webhook: str
+    enabled: bool = True
+
+
+class TelegramConfig(BaseModel):
+    """Telegram notification configuration"""
+    token: str
+    chat_id: int
+    enabled: bool = True
+
+
+class NotificationFilters(BaseModel):
+    """Notification filters configuration"""
+    case_insensitive: Dict[str, str] = {}
+    case_sensitive: Optional[Dict[str, str]] = None
+    amount_threshold: Optional[float] = None
+    keywords: List[str] = []
+
+
+class NotificationSettings(BaseModel):
+    """Complete notification settings"""
+    discord: Optional[DiscordConfig] = None
+    telegram: Optional[TelegramConfig] = None
+    filters: NotificationFilters = NotificationFilters()
+
+
+class NotificationTest(BaseModel):
+    """Test notification request"""
+    service: str  # "discord" or "telegram"
+    message: str = "Test notification from Leggen"
+
+
+class NotificationHistory(BaseModel):
+    """Notification history entry"""
+    id: str
+    service: str
+    message: str
+    status: str  # "sent", "failed"
+    sent_at: str
+    error: Optional[str] = None

leggend/api/models/sync.py

@@ -0,0 +1,55 @@
+from datetime import datetime
+from typing import Optional, Dict, Any
+
+from pydantic import BaseModel
+
+
+class SyncRequest(BaseModel):
+    """Request to trigger a sync"""
+    account_ids: Optional[list[str]] = None  # If None, sync all accounts
+    force: bool = False  # Force sync even if recently synced
+
+
+class SyncStatus(BaseModel):
+    """Sync operation status"""
+    is_running: bool
+    last_sync: Optional[datetime] = None
+    next_sync: Optional[datetime] = None
+    accounts_synced: int = 0
+    total_accounts: int = 0
+    transactions_added: int = 0
+    errors: list[str] = []
+    
+    class Config:
+        json_encoders = {
+            datetime: lambda v: v.isoformat() if v else None
+        }
+
+
+class SyncResult(BaseModel):
+    """Result of a sync operation"""
+    success: bool
+    accounts_processed: int
+    transactions_added: int
+    transactions_updated: int
+    balances_updated: int
+    duration_seconds: float
+    errors: list[str] = []
+    started_at: datetime
+    completed_at: datetime
+    
+    class Config:
+        json_encoders = {
+            datetime: lambda v: v.isoformat()
+        }
+
+
+class SchedulerConfig(BaseModel):
+    """Scheduler configuration model"""
+    enabled: bool = True
+    hour: Optional[int] = 3
+    minute: Optional[int] = 0
+    cron: Optional[str] = None  # Custom cron expression
+    
+    class Config:
+        extra = "forbid"