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>

lang/da.json

@@ -669,7 +669,23 @@
   "m365_smtp_test": "Test",
   "m365_smtp_testing": "Sender test-email…",
   "m365_smtp_test_ok": "Test-email sendt",
+  "m365_smtp_test_ok_graph": "Test-email sendt via Microsoft Graph til",
+  "m365_smtp_test_ok_smtp": "Test-email sendt via SMTP til",
+  "m365_smtp_graph_also_failed": "(⚠ Graph mislykkedes også — Mail.Send ikke tildelt)",
   "m365_smtp_test_fail": "Forbindelse mislykkedes",
+  "bulk_select_mode": "Vælg",
+  "bulk_select_all": "Vælg alle synlige",
+  "bulk_deselect_all": "Fravælg alle",
+  "bulk_apply": "Anvend",
+  "bulk_done": "Afslut",
+  "bulk_selected": "valgt",
+  "bulk_applied": "opdateret",
+  "disp_stats_total": "total",
+  "disp_stats_unreviewed": "ikke gennemgået",
+  "disp_stats_retain": "behold",
+  "disp_stats_delete": "slet",
+  "disp_stats_other": "andet",
+  "disp_stats_reviewed": "gennemgået",
   "m365_fsrc_edit_btn": "Rediger",
   "m365_fsrc_save_changes": "Gem ændringer",
   "m365_settings_tab_scheduler": "Planlægger",
@@ -793,5 +809,19 @@
   "viewer_pin_saving": "Gemmer…",
   "viewer_pin_saved": "PIN gemt",
   "viewer_pin_clear_confirm": "Fjern seerens PIN? /view vil igen kræve et token-link.",
-  "viewer_pin_cleared": "PIN ryddet"
+  "viewer_pin_cleared": "PIN ryddet",
+
+  "interface_pin_group_title": "Interface-PIN",
+  "interface_pin_desc": "En numerisk PIN-kode (4\u20138 cifre), der skal indtastes, inden man får adgang til selve scanneren. Seere, der tilgår <code style=\"font-size:10px\">/view</code>, er ikke berørt.",
+  "interface_pin_clear": "Ryd PIN",
+  "interface_pin_is_set": "Interface-PIN er angivet",
+  "interface_pin_not_set_msg": "Ingen PIN angivet \u2014 grænsefladen er åben for alle på netværket",
+  "interface_pin_saved": "PIN gemt",
+  "interface_pin_clear_confirm": "Fjern interface-PIN? Scanneren vil herefter være tilgængelig for alle på netværket.",
+  "interface_pin_cleared": "PIN ryddet",
+  "interface_pin_login_desc": "Indtast interface-PIN for at fortsætte.",
+  "interface_pin_login_btn": "Fortsæt",
+  "interface_pin_err_incorrect": "Forkert PIN.",
+  "interface_pin_err_too_many": "For mange forsøg. Prøv igen om lidt.",
+  "interface_pin_err_network": "Netværksfejl. Prøv igen."
 }