feat: profile avatar + tombstone-restore fix + WebView2 nav race + sync summary

Profile picture / avatar
- users.avatar_b64 column (nullable, cosmetic, not encrypted) + GET/POST
  /avatar endpoints mirroring the settings handler pattern.
- Top-right chip + Settings→Account show a round avatar: custom picture
  if set, otherwise the username's initial on a deterministic
  hash-picked colour (stable across renders).
- Upload downscales + center-crops to a 128px JPEG via FileReader →
  data: URI (NOT blob:, which the CSP's `img-src 'self' data:` blocks)
  before POSTing. Remove button clears it.
- Carried in the encrypted JSON export; restored on import only when the
  current account has no picture (never clobbers a local one).

Tombstone restore-then-sync fix
- POST /entries and POST /entries/bulk-import now DELETE any tombstone
  matching an inserted uuid (same transaction) so a restored backup
  isn't re-killed on the next sync by its own stale tombstone.
- applyRemoteSnapshot arbitrates remote tombstones by timestamp: a
  tombstone is skipped when the local entry with that uuid is newer than
  deleted_at (resurrection wins). Ties / unparseable timestamps favour
  KEEP. loadEntries() up front so updated_at reflects the live rows.

WebView2 navigation race
- Black-window-on-cold-start fix: the 1.5s nav timer no longer consumes
  FPendingURL when WebView2 isn't initialised yet (it re-arms, bounded
  to ~10 retries). FBrowserInitialized flag set in OnInitialized; after
  the retry budget we Navigate best-effort rather than loop forever.

Sync UX
- Bidirectional toast: "pulled X new · Y updated · Z deleted · pushed N
  entries" so a 0/0/0 pull still shows the vault was uploaded.
- FolderPOST/PUT: pre-declare ftString on color/icon params (fixes the
  earlier [SQLite]-335 on NULL bind, already in play for CSV import).

Docs
- CLAUDE.md sync section documents tombstone purge-on-insert +
  resurrection arbitration.

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

delphi-backend/Source/PM.Database.pas

@@ -370,6 +370,10 @@ begin
   // toggles (quick-unlock DPAPI, Win32 autofill hotkey) intentionally stay
   // in localStorage and are NOT included here.
   AddColumnIfMissing('users',         'settings_json',     'TEXT DEFAULT ''{}''');
+  // Profile picture: base64 data URI (nullable). Cosmetic, not encrypted.
+  // Kept in its own column rather than settings_json so it isn't shipped
+  // on every settings GET/PUT (an image is 5-50 KB).
+  AddColumnIfMissing('users',         'avatar_b64',        'TEXT');
   AddColumnIfMissing('sessions',      'csrf_token',        'TEXT');
 end;