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>

frontend/src/pages/Import.tsx

@@ -2,6 +2,7 @@ import { useEffect, useState } from "react";
 import {
   api, isAdmin,
   type Entity, type EntityType, type CapitalImportPreview, type BatchCapitalImportResult,
+  type BtcPricesStatus,
 } from "../api";
 import { useAuth } from "../context/AuthContext";
 import { formatDate, formatMoneyExact } from "../format";
@@ -383,6 +384,8 @@ export default function Import() {
 
       {!memberPv && !result && <BatchBackfill entities={entities} />}
 
+      {!memberPv && !result && <BtcPrices />}
+
       {confirmReplace && (
         <div className="fixed inset-0 bg-black/40 flex items-center justify-center p-4 z-50">
           <div className="bg-white rounded-lg p-6 max-w-md w-full">
@@ -542,3 +545,78 @@ function BatchBackfill({ entities }: { entities: Entity[] }) {
     </div>
   );
 }
+
+// BTC/USD price history for the bitcoin-denominated LP view: upload a CSV (date + close
+// price); statements are valued at the newest price on or before their date, and paid-in
+// at the price on each fund's close date (set on the fund's overview page).
+function BtcPrices() {
+  const [status, setStatus] = useState<BtcPricesStatus | null>(null);
+  const [file, setFile] = useState<File | null>(null);
+  const [busy, setBusy] = useState(false);
+  const [error, setError] = useState("");
+  const [msg, setMsg] = useState("");
+
+  useEffect(() => {
+    api.btcPricesStatus().then(setStatus).catch(() => {});
+  }, []);
+
+  async function run() {
+    if (!file) return;
+    setError("");
+    setMsg("");
+    setBusy(true);
+    try {
+      const r = await api.importBtcPrices(file);
+      setStatus(r);
+      setMsg(
+        `Loaded ${r.imported} price${r.imported === 1 ? "" : "s"}` +
+          (r.skipped_rows ? ` (${r.skipped_rows} unreadable row${r.skipped_rows === 1 ? "" : "s"} skipped)` : "") +
+          ".",
+      );
+      setFile(null);
+    } catch (e: any) {
+      setError(e.message || "Price import failed");
+    } finally {
+      setBusy(false);
+    }
+  }
+
+  return (
+    <div className="mt-10 border-t border-gray-200 pt-8">
+      <h2 className="text-lg font-semibold text-gray-900 mb-1">Bitcoin prices</h2>
+      <p className="text-sm text-gray-500 mb-3">
+        Upload a CSV of BTC/USD prices (a date column and a close/price column). Investors
+        then see their capital in bitcoin terms; paid-in is valued at the price on each
+        fund's close date — set that on the fund's overview page.
+      </p>
+      {status && status.count > 0 && (
+        <p className="text-xs text-gray-400 mb-3">
+          {status.count} prices on file
+          {status.first_date && status.last_date && (
+            <> · {formatDate(status.first_date)} → {formatDate(status.last_date)}</>
+          )}
+          {status.latest_price_cents != null && (
+            <> · latest ${(status.latest_price_cents / 100).toLocaleString()}</>
+          )}
+        </p>
+      )}
+      <div className="flex flex-wrap items-center gap-3">
+        <input
+          type="file"
+          accept=".csv"
+          onChange={(e) => setFile(e.target.files?.[0] ?? null)}
+          className="text-sm"
+        />
+        <button
+          onClick={run}
+          disabled={busy || !file}
+          className="px-3 py-1.5 bg-brand-900 text-white text-sm rounded hover:bg-brand-800 disabled:opacity-50"
+        >
+          {busy ? "Loading…" : "Load prices"}
+        </button>
+      </div>
+      {error && <p className="text-sm text-red-600 mt-2">{error}</p>}
+      {msg && <p className="text-sm text-green-700 mt-2">{msg}</p>}
+    </div>
+  );
+}