Track a transferred saint's origin date on DayWinner and Commemoration

Adds transferredFrom to both DayWinner's sanctoral variant and
Commemoration's sanctoral variant, set in calendar/index.ts's
applyIncomingTransfer whenever a transferred-in candidate actually lands
(wins outright) or ends up merely commemorated (lost a collision, or fell
below the landing day's own threshold) — previously this signal was
discarded after resolveDay used it once to decide the winner, so nothing
downstream could tell a transferred feast apart from a native one.

Also adds transferredAway to LiturgicalDay, set from a date's own native
occurrence when its candidate couldn't be kept there at all, so a UI can
note "this office moved elsewhere" without asserting a specific landing
date (which a later, unmodeled multi-hop chain — e.g. into Holy Week —
could get wrong).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013g7AsSvMD9oazR17f3BxLz

tests/calendar/transfer.test.ts

@@ -28,7 +28,14 @@ describe('transfer mechanism (resolveDay integration)', () => {
       rank: 'semiduplex',
     });
     expect(saturday.commemorations).toEqual([
-      { kind: 'sanctoral', id: 'vigil-of-st-lawrence', name: 'Vigil of St. Lawrence', nameLa: 'Vigilia Sancti Laurentii', rank: 'vigil' },
+      {
+        kind: 'sanctoral',
+        id: 'vigil-of-st-lawrence',
+        name: 'Vigil of St. Lawrence',
+        nameLa: 'Vigilia Sancti Laurentii',
+        rank: 'vigil',
+        transferredFrom: '2026-08-09',
+      },
     ]);
 
     // The Sunday's own winner is unaffected by the vigil, but St. Romanus