0.2.39: bitcoin-denominated view, first-login flow, unfunded + tax center

- BTC prices: btc_prices table, CSV upload on Import page (auto-detected
  date/close columns, upsert by date), entities.close_date as the BTC entry
  mark; statements carry btc_price_cents (as-of) + btc_close_price_cents.
  LP capital blocks show paid-in vs current value in bitcoin terms.
- First login: accounts on the shared default password are flagged
  (must_change_password) and blocked behind a full-screen password change;
  external accounts then get a one-time welcome tour with a 2FA offer
  (users.onboarded_at).
- LP portal: Unfunded (callable commitment) metric; Tax documents center
  aggregating K-1/tax docs across funds, grouped by year.

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

backend/ten31portal/routers/capital_account_router.py

@@ -1,5 +1,7 @@
 """Capital account statements: admin entry, investor read of their own figures."""
 
+from bisect import bisect_right
+
 from fastapi import APIRouter, Depends, HTTPException
 from sqlmodel import Session, select, col
 
@@ -10,7 +12,7 @@ from ten31portal.auth import (
 )
 from ten31portal.database import get_session
 from ten31portal.models import (
-    CapitalAccountStatement, Entity, EntityAccess, User, UserRole,
+    BtcPrice, CapitalAccountStatement, Entity, EntityAccess, User, UserRole,
 )
 from ten31portal.schemas import CapitalAccountCreate, CapitalAccountResponse
 
@@ -37,6 +39,33 @@ def exit_dates(session: Session, rows) -> dict:
     }
 
 
+def btc_marks(session: Session, rows) -> tuple[dict, dict]:
+    """BTC/USD marks for the bitcoin-denominated view.
+
+    Returns ({statement_id: price at its as-of date}, {entity_id: price at the fund's
+    close date}) — "price at" meaning the newest uploaded price on or before that date,
+    so a quarter-end-only CSV is enough. Empty when no prices are uploaded; a fund without
+    a close_date has no entry and the portal hides its BTC view.
+    """
+    if not rows:
+        return {}, {}
+    prices = session.exec(select(BtcPrice).order_by(col(BtcPrice.date))).all()
+    if not prices:
+        return {}, {}
+    dates = [p.date for p in prices]
+
+    def price_at(d):
+        i = bisect_right(dates, d)
+        return prices[i - 1].price_cents if i else None
+
+    asof = {r.id: price_at(r.as_of_date) for r in rows}
+    entities = session.exec(
+        select(Entity).where(col(Entity.id).in_({r.entity_id for r in rows}))
+    ).all()
+    close = {e.id: price_at(e.close_date) for e in entities if e.close_date is not None}
+    return asof, close
+
+
 @router.get("")
 def list_statements(
     entity_id: int | None = None,
@@ -74,11 +103,14 @@ def list_statements(
         )
     ).all()) if rows else {}
     exits = exit_dates(session, rows)
+    btc_asof, btc_close = btc_marks(session, rows)
     out: list[CapitalAccountResponse] = []
     for r in rows:
         data = CapitalAccountResponse.model_validate(r, from_attributes=True)
         data.investor_name = names.get(r.investor_user_id)
         data.exited_on = exits.get((r.investor_user_id, r.entity_id))
+        data.btc_price_cents = btc_asof.get(r.id)
+        data.btc_close_price_cents = btc_close.get(r.entity_id)
         out.append(data)
     return out