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/Source/PM.Database.pas

@@ -189,6 +189,25 @@ begin
     '  created_at DATETIME DEFAULT CURRENT_TIMESTAMP,' +
     '  FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE' +
     ')');
+  // Password history — keeps the last N versions of each entry's
+  // encrypted_password + iv. Populated by HandleUpdateEntry before each
+  // PUT overwrites the row; pruned to 20 entries per row after each insert.
+  // kind mirrors vault_entries.kind so notes can be restored too.
+  FConn.ExecSQL(
+    'CREATE TABLE IF NOT EXISTS entries_password_history (' +
+    '  id INTEGER PRIMARY KEY AUTOINCREMENT,' +
+    '  entry_id INTEGER NOT NULL,' +
+    '  user_id INTEGER NOT NULL,' +
+    '  encrypted_password TEXT NOT NULL,' +
+    '  iv TEXT NOT NULL,' +
+    '  kind TEXT NOT NULL DEFAULT ''login'',' +
+    '  changed_at DATETIME DEFAULT CURRENT_TIMESTAMP,' +
+    '  FOREIGN KEY (entry_id) REFERENCES vault_entries(id) ON DELETE CASCADE,' +
+    '  FOREIGN KEY (user_id)  REFERENCES users(id)         ON DELETE CASCADE' +
+    ')');
+  FConn.ExecSQL(
+    'CREATE INDEX IF NOT EXISTS idx_history_entry ' +
+    '  ON entries_password_history(entry_id, changed_at DESC)');
 end;
 
 function TPMDatabase.ColumnExists(const ATable, AColumn: string): Boolean;
@@ -241,6 +260,17 @@ begin
   // sees the plaintext secret. NULL = no TOTP configured for this entry.
   AddColumnIfMissing('vault_entries', 'totp_secret',       'TEXT');
   AddColumnIfMissing('vault_entries', 'totp_iv',           'TEXT');
+  // Entry kind: 'login' (default — site/user/encrypted_password/iv/totp)
+  // or 'note' (free-text secure note — body stored in encrypted_password
+  // + iv, site/username/totp_* unused). Legacy rows default to 'login'.
+  AddColumnIfMissing('vault_entries', 'kind',              'TEXT DEFAULT ''login''');
+  // Custom fields: opaque encrypted JSON array of
+  //   [{label, value, is_secret}, ...]
+  // Same crypto pipeline as encrypted_password (AES-GCM with the vault
+  // key). NULL = no custom fields configured. The server treats both
+  // columns as opaque ciphertext + IV.
+  AddColumnIfMissing('vault_entries', 'custom_fields',     'TEXT');
+  AddColumnIfMissing('vault_entries', 'custom_fields_iv',  'TEXT');
   // Cached favicon as a base64 data URI (e.g. "data:image/png;base64,...").
   // Fetched on demand by the Delphi favicon proxy when the user opts in.
   // NULL = no icon cached → JS falls back to the first-letter avatar.