feat: interface PIN, bulk disposition tagging, Google Drive delta scan, OCR memory fixes

- Interface PIN: optional session-level auth gate for the main scanner UI
  (Settings → Security → Interface PIN). Salted SHA-256 in config.json,
  rate-limited (5 attempts/5 min per IP). /view and viewer auth exempt.
  New /login page, before_request hook, GET/POST/DELETE /api/interface/pin,
  POST /api/interface/pin/verify, POST /api/interface/logout.

- Bulk disposition tagging: Select mode (filter bar "Vælg" button) reveals
  per-card checkboxes. Bulk tag bar at bottom of grid; POST /api/db/disposition/bulk.
  Disposition stats bar (total · unreviewed · retain · delete · % reviewed)
  updates after every save.

- Google Drive delta scan: uses Drive Changes API when delta is enabled.
  Per-user token stored as gdrive:{email} in delta.json. Load-then-merge
  save avoids racing with concurrent M365 token writes.

- PDF OCR OOM fix: render one page at a time with convert_from_path
  (first_page=N, last_page=N). Added _ocr_mem_ok() psutil guard (500 MB
  threshold) before each page render across scan_pdf, redact_fitz_pdf,
  redact_pdf.

- Email test message translation fix: routes/email.py returns structured
  {ok, method, recipients} instead of a hardcoded English string;
  scheduler.js builds the translated message client-side.

- Docs: CHANGELOG, README, TODO, MANUAL-EN, MANUAL-DA all updated.
  Lang files (en/da/de) extended with bulk, interface PIN, and SMTP keys.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

static/js/viewer.js

@@ -374,6 +374,85 @@ async function stClearViewerPin() {
   }
 }
 
+// ── Interface PIN — Settings UI ───────────────────────────────────────────────
+
+async function stLoadInterfacePinStatus() {
+  try {
+    const r = await fetch('/api/interface/pin');
+    const d = await r.json();
+    const statusEl   = document.getElementById('stInterfacePinStatus');
+    const currentRow = document.getElementById('stInterfaceCurrentPinRow');
+    const clearBtn   = document.getElementById('stInterfacePinClearBtn');
+    if (d.pin_set) {
+      if (statusEl)   statusEl.textContent   = '\u2714 ' + t('interface_pin_is_set', 'Interface PIN is set');
+      if (currentRow) currentRow.style.display = '';
+      if (clearBtn)   clearBtn.style.display   = '';
+    } else {
+      if (statusEl)   statusEl.textContent   = t('interface_pin_not_set_msg', 'No PIN set \u2014 interface is open to anyone on the network');
+      if (currentRow) currentRow.style.display = 'none';
+      if (clearBtn)   clearBtn.style.display   = 'none';
+    }
+  } catch(e) {}
+}
+
+async function stSaveInterfacePin() {
+  const newPin     = (document.getElementById('stInterfaceNewPin')?.value    || '').trim();
+  const currentPin = (document.getElementById('stInterfaceCurrentPin')?.value || '').trim();
+  const st         = document.getElementById('stInterfacePinSaveStatus');
+  if (!newPin) {
+    if (st) { st.style.color = 'var(--danger)'; st.textContent = t('m365_settings_pin_required', 'PIN is required.'); }
+    return;
+  }
+  if (!/^\d{4,8}$/.test(newPin)) {
+    if (st) { st.style.color = 'var(--danger)'; st.textContent = t('viewer_pin_format', 'PIN must be 4\u20138 digits.'); }
+    return;
+  }
+  if (st) { st.style.color = 'var(--muted)'; st.textContent = t('viewer_pin_saving', 'Saving\u2026'); }
+  try {
+    const r = await fetch('/api/interface/pin', {
+      method: 'POST', headers: {'Content-Type': 'application/json'},
+      body: JSON.stringify({pin: newPin, current_pin: currentPin})
+    });
+    const d = await r.json();
+    if (!r.ok) {
+      if (st) { st.style.color = 'var(--danger)'; st.textContent = d.error || 'Error.'; }
+      return;
+    }
+    if (st) { st.style.color = 'var(--accent)'; st.textContent = '\u2714 ' + t('interface_pin_saved', 'PIN saved'); }
+    if (document.getElementById('stInterfaceNewPin'))    document.getElementById('stInterfaceNewPin').value    = '';
+    if (document.getElementById('stInterfaceCurrentPin')) document.getElementById('stInterfaceCurrentPin').value = '';
+    stLoadInterfacePinStatus();
+  } catch(e) {
+    if (st) { st.style.color = 'var(--danger)'; st.textContent = e.message; }
+  }
+}
+
+async function stClearInterfacePin() {
+  const currentPin = (document.getElementById('stInterfaceCurrentPin')?.value || '').trim();
+  const st         = document.getElementById('stInterfacePinSaveStatus');
+  if (!currentPin) {
+    if (st) { st.style.color = 'var(--danger)'; st.textContent = t('m365_settings_pin_required', 'PIN is required.'); }
+    document.getElementById('stInterfaceCurrentPin')?.focus();
+    return;
+  }
+  if (!confirm(t('interface_pin_clear_confirm', 'Remove the interface PIN? The scanner will be accessible to anyone on the network.'))) return;
+  try {
+    const r = await fetch('/api/interface/pin', {
+      method: 'DELETE', headers: {'Content-Type': 'application/json'},
+      body: JSON.stringify({current_pin: currentPin})
+    });
+    const d = await r.json();
+    if (!r.ok) {
+      if (st) { st.style.color = 'var(--danger)'; st.textContent = d.error || 'Error.'; }
+      return;
+    }
+    if (st) { st.style.color = 'var(--muted)'; st.textContent = t('interface_pin_cleared', 'PIN cleared'); }
+    stLoadInterfacePinStatus();
+  } catch(e) {
+    if (st) { st.style.color = 'var(--danger)'; st.textContent = e.message; }
+  }
+}
+
 // ── Window exports ────────────────────────────────────────────────────────────
 window._shareScopeTypeChanged = _shareScopeTypeChanged;
 window.openShareModal       = openShareModal;
@@ -382,6 +461,9 @@ window.createShareLink      = createShareLink;
 window.copyShareLink        = copyShareLink;
 window.copyTokenLink        = copyTokenLink;
 window.revokeToken          = revokeToken;
-window.stLoadViewerPinStatus = stLoadViewerPinStatus;
-window.stSaveViewerPin      = stSaveViewerPin;
-window.stClearViewerPin     = stClearViewerPin;
+window.stLoadViewerPinStatus  = stLoadViewerPinStatus;
+window.stSaveViewerPin        = stSaveViewerPin;
+window.stClearViewerPin       = stClearViewerPin;
+window.stLoadInterfacePinStatus = stLoadInterfacePinStatus;
+window.stSaveInterfacePin     = stSaveInterfacePin;
+window.stClearInterfacePin    = stClearInterfacePin;