Add pension PDF upload, parsing, and fund summary API

Backend: parse BAC pension statement PDFs (VOL, ROP, FCL) via
pdftotext, store snapshots with duplicate detection, reject
credit card statements. Endpoints: POST /upload, GET /snapshots,
GET /fund-summary.

Frontend: wire up drag-and-drop upload, load real balances and
rendimientos from API, show upload results with error/duplicate
feedback.

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

backend/app/models/models.py

@@ -1,8 +1,8 @@
 import enum
-from datetime import datetime
+from datetime import date, datetime
 from typing import Optional
 
-from sqlalchemy import JSON, Column
+from sqlalchemy import JSON, Column, UniqueConstraint
 from sqlmodel import Field, Relationship, SQLModel
 
 
@@ -300,3 +300,36 @@ class PushSubscription(SQLModel, table=True):
 class PushSubscriptionCreate(SQLModel):
     endpoint: str
     keys: dict  # {"p256dh": "...", "auth": "..."}
+
+
+# --- Pension Snapshot ---
+
+
+class PensionSnapshotBase(SQLModel):
+    fund: Bank
+    contract_number: str
+    period_start: date
+    period_end: date
+    saldo_anterior: float
+    aportes: float
+    rendimientos: float
+    retiros: float
+    traslados: float
+    comision: float
+    correccion: float
+    bonificacion: float
+    saldo_final: float
+    source_filename: str
+
+
+class PensionSnapshot(PensionSnapshotBase, table=True):
+    __table_args__ = (
+        UniqueConstraint("fund", "period_start", "period_end"),
+    )
+    id: Optional[int] = Field(default=None, primary_key=True)
+    created_at: datetime = Field(default_factory=datetime.utcnow)
+
+
+class PensionSnapshotRead(PensionSnapshotBase):
+    id: int
+    created_at: datetime