Add accounts expansion, analytics, exchange rates, API tokens, PWA support, and UI overhaul

- Expand Account model with account_type (pension, savings, liability, crypto), new banks/currencies (BTC, XMR, FCL, ROP, VOL, MEMP, MPAT, MORTGAGE), and next_payment field
- Add exchange rate endpoint (BCCR integration), analytics endpoint, paste-import for transactions, and API token management
- Add PWA manifest, service worker, and app icons
- Redesign dashboard, transactions, transfers, and login pages with theme support
- Add billing cycle selector, confirm dialog, and paste import modal components
- One-time DB reset in deploy workflow for schema migration

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/app/api/v1/endpoints/transactions.py

@@ -1,7 +1,9 @@
+from datetime import datetime
 from typing import Optional
 
 from fastapi import APIRouter, Depends, HTTPException, Query
-from sqlmodel import Session, col, select
+from pydantic import BaseModel
+from sqlmodel import Session, col, func, select
 
 from app.auth import get_current_user
 from app.db import get_session
@@ -17,6 +19,24 @@ from app.models.models import (
 router = APIRouter(prefix="/transactions", tags=["transactions"])
 
 
+def get_cycle_range(year: int, month: int) -> tuple[datetime, datetime]:
+    """Return (start, end) for billing cycle: month/18 to month+1/18."""
+    start = datetime(year, month, 18)
+    if month == 12:
+        end = datetime(year + 1, 1, 18)
+    else:
+        end = datetime(year, month + 1, 18)
+    return start, end
+
+
+class BillingCycle(BaseModel):
+    year: int
+    month: int
+    label: str
+    count: int
+    total: float
+
+
 def auto_categorize(merchant: str, session: Session) -> Optional[int]:
     categories = session.exec(select(Category)).all()
     merchant_lower = merchant.lower()
@@ -33,6 +53,8 @@ def list_transactions(
     source: Optional[TransactionSource] = None,
     search: Optional[str] = None,
     category_id: Optional[int] = None,
+    cycle_year: Optional[int] = None,
+    cycle_month: Optional[int] = None,
     limit: int = Query(default=50, le=500),
     offset: int = 0,
     session: Session = Depends(get_session),
@@ -45,10 +67,72 @@ def list_transactions(
         query = query.where(Transaction.category_id == category_id)
     if search:
         query = query.where(col(Transaction.merchant).ilike(f"%{search}%"))
+    if cycle_year and cycle_month:
+        start, end = get_cycle_range(cycle_year, cycle_month)
+        query = query.where(Transaction.date >= start, Transaction.date < end)
     query = query.order_by(col(Transaction.date).desc()).offset(offset).limit(limit)
     return session.exec(query).all()
 
 
+@router.get("/cycles", response_model=list[BillingCycle])
+def list_billing_cycles(
+    session: Session = Depends(get_session),
+    _user: str = Depends(get_current_user),
+):
+    """Return available billing cycles based on transaction dates."""
+    # Get date range of all transactions
+    result = session.exec(
+        select(func.min(Transaction.date), func.max(Transaction.date))
+    ).first()
+    if not result or not result[0]:
+        return []
+
+    min_date, max_date = result
+
+    cycles = []
+    # Determine which cycle the min_date falls into
+    if min_date.day < 18:
+        # Falls in previous month's cycle
+        if min_date.month == 1:
+            y, m = min_date.year - 1, 12
+        else:
+            y, m = min_date.year, min_date.month - 1
+    else:
+        y, m = min_date.year, min_date.month
+
+    while True:
+        start, end = get_cycle_range(y, m)
+        if start > max_date:
+            break
+
+        # Count transactions in this cycle
+        count_result = session.exec(
+            select(func.count(), func.coalesce(func.sum(Transaction.amount), 0)).where(
+                Transaction.date >= start, Transaction.date < end
+            )
+        ).first()
+        count = count_result[0] if count_result else 0
+        total = float(count_result[1]) if count_result else 0.0
+
+        if count > 0:
+            month_names = [
+                "", "Jan", "Feb", "Mar", "Apr", "May", "Jun",
+                "Jul", "Aug", "Sep", "Oct", "Nov", "Dec",
+            ]
+            end_month = m + 1 if m < 12 else 1
+            end_year = y if m < 12 else y + 1
+            label = f"{month_names[m]} 18 - {month_names[end_month]} 18, {end_year}"
+            cycles.append(BillingCycle(year=y, month=m, label=label, count=count, total=total))
+
+        # Next month
+        if m == 12:
+            y, m = y + 1, 1
+        else:
+            m += 1
+
+    return list(reversed(cycles))
+
+
 @router.get("/recent", response_model=list[TransactionRead])
 def recent_transactions(
     limit: int = Query(default=5, le=20),
@@ -71,6 +155,16 @@ def create_transaction(
     _user: str = Depends(get_current_user),
 ):
     tx = Transaction.model_validate(data)
+    # Duplicate detection by reference
+    if tx.reference:
+        existing = session.exec(
+            select(Transaction).where(Transaction.reference == tx.reference)
+        ).first()
+        if existing:
+            raise HTTPException(
+                status_code=409,
+                detail=f"Duplicate transaction: reference '{tx.reference}' already exists (id={existing.id})",
+            )
     if tx.category_id is None:
         tx.category_id = auto_categorize(tx.merchant, session)
     session.add(tx)