fix(sync): resurrect tombstoned annotations when a newer save re-creates them

Deleting a bookmark/highlight/note and then re-adding the same content
at the same position (same dedup key — e.g. the reader's auto-titled
'Bookmark at X%') was silently swallowed: the save hit the tombstone
branch, returned 201 with the deleted row, and the list (which filters
deleted) stayed empty. Bookmarks were further blocked by the
UNIQUE(media_item_id, user_id, title) slot the tombstoned row holds,
and notes had no TTL escape at all.

Tombstones now only block saves that predate them (stale replays from
a device that still has the annotation). A save whose modification
time is newer than max(deleted_at, last_modified_at) — a deliberate
re-create from the web or a device — resurrects the row via the LWW
update queries, which now clear deleted/deleted_at.

internal/database/queries/queries.sql

@@ -802,7 +802,9 @@ UPDATE media_highlights SET
     last_modified_at = $12,
     last_modified_source = $13,
     device_sync_data = $14,
-    updated_at = NOW()
+    updated_at = NOW(),
+    deleted = FALSE,
+    deleted_at = NULL
 WHERE id = $1
 RETURNING *;
 
@@ -857,7 +859,9 @@ UPDATE media_notes SET
     last_modified_at = $10,
     last_modified_source = $11,
     device_sync_data = $12,
-    updated_at = NOW()
+    updated_at = NOW(),
+    deleted = FALSE,
+    deleted_at = NULL
 WHERE id = $1
 RETURNING *;
 
@@ -913,7 +917,9 @@ UPDATE media_bookmarks SET
     last_modified_at = $11,
     last_modified_source = $12,
     device_sync_data = $13,
-    created_at = created_at
+    created_at = created_at,
+    deleted = FALSE,
+    deleted_at = NULL
 WHERE id = $1
 RETURNING *;