feat: secure notes + password history + custom fields + quick-win bundle

Big feature trio
- Secure notes (kind='login'|'note') reusing the encrypted_password+iv
  pipeline for the body. New sidebar entry, slideover variant (title +
  multiline body), distinct card / table-view rendering, badge in name
  column, copy-content button replacing the password copy on note rows.
- Password history: entries_password_history table keeps up to 20 prior
  ciphertexts per entry. HandleUpdateEntry pushes the pre-update
  encrypted_password into history ONLY when it actually differs from
  the incoming one (JS reuses originalEncrypted bit-for-bit when the
  plaintext is unchanged — avoids spamming history on title/folder edits).
  GET /entries/{id}/history endpoint. Slideover modal lists versions
  with mask/reveal/copy/revert. Master-pw rotation wipes history (old
  ciphertext can't be decrypted with the new key).
- Custom fields: per-entry encrypted JSON array of {label, value,
  is_secret}. Same crypto pipeline as the password. Slideover row UI
  with label/value inputs, secret toggle (eye), copy, delete. Re-
  encryption flows through bulk-import, change-master-password, and
  duplicate.

Quick wins
- Cheatsheet overlay (press '?' or topbar button or Ctrl+K). Lists all
  hotkeys + global / tray / card actions. SVG icons inline so the
  cheatsheet matches the actual app glyphs (no emoji mismatch).
- Open URL button on entry cards: ShellExecute via cmd://app/open-url,
  http(s) only, validates entry.site looks like a real hostname.
- Trash auto-purge: setting "Empty trash after N days" (never/7/30/90).
  DELETE /entries/trash/old?days=N called at every unlock.

Favicon strategy
- Subdomains (chat.deepseek.com, app.X.com…) now try the SLD first
  (deepseek.com.ico) before the full host. DDG often returns a generic
  placeholder for subdomains that passes the byte threshold; the SLD-first
  switch surfaces the real brand icon.
- Cap bumped 64 KB → 256 KB on all three sides (Delphi fetch, server
  endpoint, JS upload). DDG sometimes serves the full-res asset.

UX polish
- Click-outside-slideover: stopPropagation everywhere it bites. Custom
  fields buttons (add / delete / secret toggle / copy / eye) all stop
  the click bubble so the document-level "close on outside click" handler
  doesn't fire when rerender() detaches the target from the DOM.
- Native search-cancel button restyled: cyan accent X via mask-image,
  cursor: pointer, breathing room before the Ctrl+K kbd chip.
- Password history modal: scrollable body, multiline wrapped passwords,
  hover border highlight.
- Cheatsheet panel widened (560 → 720 px) so the descriptions no longer
  ellipsis-clip.
- "+ New" topbar splits into a small dropdown: New login / New note.
- Notes show a "note" badge in table-view name column, italic
  "Encrypted note" placeholder in the username column.

Internals
- duplicateEntry copies kind + custom_fields too (one-line forgotten
  earlier).
- entries_password_history dropped on master-pw rotation — the old
  ciphertexts are unrecoverable with the new key.
- bulk-import re-encryption path includes custom_fields.

CLAUDE.md
- "Entry payload — call sites à toucher ensemble" lists the 6 spots
  to update when adding a new (en)crypted field. Notes the historical
  miss of kind in duplicateEntry and custom_fields in the rotation +
  duplicate.

Repo hygiene
- .gitattributes forces CRLF on Delphi sources (RAD Studio refuses LF).
  text=auto for web frontend / docs, binary for .res / .exe / images.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

delphi-backend/Handlers/PM.Handler.Auth.pas

@@ -918,6 +918,7 @@ begin
             'UPDATE vault_entries SET ' +
             '  encrypted_password = :ep, iv = :iv, ' +
             '  totp_secret = :ts, totp_iv = :tiv, ' +
+            '  custom_fields = :cf, custom_fields_iv = :cfiv, ' +
             '  updated_at = CURRENT_TIMESTAMP ' +
             'WHERE id = :id AND user_id = :uid';
 
@@ -929,6 +930,8 @@ begin
             LIv      := LEntry.GetValue<string>('iv', '');
             LTotpSec := LEntry.GetValue<string>('totp_secret', '');
             LTotpIv  := LEntry.GetValue<string>('totp_iv', '');
+            var LCf   := LEntry.GetValue<string>('custom_fields', '');
+            var LCfIv := LEntry.GetValue<string>('custom_fields_iv', '');
             if (LEntryId <= 0) or (LEncPwd = '') or (LIv = '') then
               raise Exception.CreateFmt('Invalid entry payload at index %d', [I]);
 
@@ -936,18 +939,31 @@ begin
             LQ.ParamByName('uid').AsInteger := LUserId;
             LQ.ParamByName('ep').AsString   := LEncPwd;
             LQ.ParamByName('iv').AsString   := LIv;
-            // TOTP fields are optional per entry — clear when empty so
-            // existing-NULL rows don't get stomped with empty strings.
-            LQ.ParamByName('ts').DataType := ftString;
-            LQ.ParamByName('tiv').DataType := ftString;
-            if LTotpSec.IsEmpty then
-              LQ.ParamByName('ts').Clear
-            else
-              LQ.ParamByName('ts').AsString := LTotpSec;
+            // TOTP / custom_fields are optional per entry — clear when
+            // empty so existing-NULL rows don't get stomped with empty strings.
+            LQ.ParamByName('ts').DataType   := ftString;
+            LQ.ParamByName('tiv').DataType  := ftString;
+            LQ.ParamByName('cf').DataType   := ftString;
+            LQ.ParamByName('cfiv').DataType := ftString;
+            if LTotpSec.IsEmpty then LQ.ParamByName('ts').Clear
+            else                      LQ.ParamByName('ts').AsString := LTotpSec;
             if LTotpIv = '' then LQ.ParamByName('tiv').Clear
             else                  LQ.ParamByName('tiv').AsString := LTotpIv;
+            if LCf = '' then LQ.ParamByName('cf').Clear
+            else              LQ.ParamByName('cf').AsString := LCf;
+            if LCfIv = '' then LQ.ParamByName('cfiv').Clear
+            else                LQ.ParamByName('cfiv').AsString := LCfIv;
             LQ.ExecSQL;
           end;
+          // Password history is encrypted with the OLD vault key — we
+          // don't ship the plaintext server-side to re-encrypt it under
+          // the new key. Drop the history rows so a future "Show history"
+          // doesn't surface undecryptable garbage. The user accepts this
+          // as a consequence of rotating their master password.
+          LQ.SQL.Text :=
+            'DELETE FROM entries_password_history WHERE user_id = :uid';
+          LQ.ParamByName('uid').AsInteger := LUserId;
+          LQ.ExecSQL;
         finally
           LQ.Free;
         end;