List each account's statement files, and open them

The Accounts screen gets a Statements list: every file in every account
folder beside what the index made of it -- imported, changed since,
not imported yet (or failed), or gone from disk while its rows remain --
with its size, modified and import times, and how many transactions it
brought in. Clicking a name opens the file.

The list is read from the folders, not the index, through
importer.StatementFiles, so a file shows exactly when import would read
it; store.SourceFiles and importer.Checksum then say how far each has
got. A file the index remembers but the disk lost is listed as missing
rather than vanishing, since its rows would not survive a rebuild.

A file is served only by finding it in that list, never by joining the
requested name onto a path. Statements come from outside and are served
from the app's origin, so none is rendered as a page: text is text/plain
under CSP sandbox, anything not text or PDF is a sandboxed download, and
PDFs -- whose viewers refuse a sandbox -- open in the browser's own
isolated viewer.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/web/static/app.js

@@ -266,13 +266,15 @@ async function retag() {
 
 function mountAccounts(main) {
   const body = h('div');
+  const files = h('div');
   const upload = h('div');
-  main.append(h('h2', {}, 'Accounts'), body, upload);
+  main.append(h('h2', {}, 'Accounts'), body, files, upload);
 
   async function refresh() {
     if (!state.overview) await loadOverview();
     const o = state.overview;
     upload.replaceChildren(uploader(o));
+    api('GET', '/api/files').then((res) => files.replaceChildren(fileList(res.files))).catch(setError);
     if (!o.accounts.length) {
       // An account.toml is not enough on its own: folders reach the index
       // only through an import, so say that rather than show nothing.
@@ -295,6 +297,63 @@ function mountAccounts(main) {
   return { refresh };
 }
 
+const FILE_STATUS = {
+  imported: ['✓', '', 'imported'],
+  changed: ['⚠', 'warn', 'changed since it was imported — Import re-reads it'],
+  new: ['•', 'warn', 'not imported — press Import (a file that fails to parse stays here)'],
+  missing: ['✗', 'neg', 'gone from disk — its rows stay only until the index is rebuilt'],
+};
+
+// fileList shows the statements in every account folder beside what the index
+// recorded about each, and opens one on click. The folders decide what is
+// listed; the index only says how far each file has got.
+function fileList(list) {
+  const panel = h('div', { class: 'panel files' });
+  if (!list.length) {
+    panel.append(h('div', { class: 'empty' }, 'No statement files yet.'));
+    return h('div', {}, h('h3', { class: 'section' }, 'Statements'), panel);
+  }
+  const pending = list.filter((f) => f.status !== 'imported').length;
+  panel.append(h('table', {},
+    h('thead', {}, h('tr', {}, h('th', {}, 'Account'), h('th', {}, 'File'), h('th', { class: 'num' }, 'Size'),
+      h('th', {}, 'Modified'), h('th', {}, ''), h('th', {}, 'Status'),
+      h('th', { class: 'num', title: 'Transactions this file brought into the index; rows already brought by an overlapping statement count there' }, 'Added'),
+      h('th', {}, 'Imported'))),
+    h('tbody', {}, list.map((f) => {
+      const [mark, cls, text] = FILE_STATUS[f.status] || ['', '', f.status];
+      return h('tr', {},
+        h('td', {}, f.account),
+        h('td', { class: 'desc' }, f.status === 'missing' ? h('span', { class: 'muted' }, f.name) : h('a', {
+          href: `/api/files/${encodeURIComponent(f.account)}/${encodeURIComponent(f.name)}`,
+          target: '_blank', rel: 'noopener', title: 'Open this statement',
+        }, f.name)),
+        h('td', { class: 'num' }, f.status === 'missing' ? '' : formatSize(f.size)),
+        h('td', { class: 'muted' }, f.modified),
+        h('td', { class: 'mark ' + cls }, mark),
+        h('td', { class: cls || 'muted' }, text),
+        h('td', { class: 'num' }, f.status === 'new' ? '' : f.added),
+        h('td', { class: 'muted' }, localTime(f.importedAt)));
+    }))));
+  return h('div', {}, h('h3', { class: 'section' }, 'Statements ',
+    h('span', { class: 'sub' }, `· ${list.length} file(s)` + (pending ? ` · ${pending} need attention` : ''))), panel);
+}
+
+// localTime shows the index's UTC import time in the same local
+// YYYY-MM-DD HH:MM that the server gives the files' modified times.
+function localTime(iso) {
+  if (!iso) return '';
+  const d = new Date(iso);
+  if (isNaN(d)) return iso;
+  const p = (n) => String(n).padStart(2, '0');
+  return `${d.getFullYear()}-${p(d.getMonth() + 1)}-${p(d.getDate())} ${p(d.getHours())}:${p(d.getMinutes())}`;
+}
+
+function formatSize(bytes) {
+  if (bytes < 1024) return `${bytes} B`;
+  if (bytes < 1024 * 1024) return `${Math.round(bytes / 1024)} KB`;
+  return `${(bytes / 1024 / 1024).toFixed(1)} MB`;
+}
+
 // uploader puts statement files into an account folder and imports them. The
 // folder is where they belong: the index is rebuilt from it, so a statement
 // that lived only in the index would be lost the next time it is deleted.