fix: address the 15 CodeRabbit findings from the wire-audit review

Security:
- roomcode PUT now requires instance ownership (any player could plant
  or relocate codes on foreign private instances)
- /platformid/{accountId} requires auth (anonymous Steam/Oculus id
  enumeration oracle)
- request tracing no longer captures successful /thread bodies by
  default (chat messages landed unredacted in logs); opt in via
  Trace__SuccessBodyPaths
- anonymous action-link renewal clamped to 720h per consume

Data integrity:
- buyPurchaseReminder upserts its objective sentinel (second purchase
  threw UNIQUE after the wallet was debited)
- progression reward gift + idempotency sentinel commit in one
  transaction (crash between them double-minted the reward)
- ClubPermissionsGalleryAndModeration migration defaults corrected to
  the entity contract (CommentsJson '[]', ClubChatEnabled true); new
  one-shot ClubChatDefaultRepair migration fixes databases that
  applied the wrong defaults; bootstrap repairs '' CommentsJson rows
- admin subroom-maxplayers audit entry commits with the mutation
- account purge covers CustomAvatarItems (ownership deleted, created
  items reassigned to the system account)
- duplicate photo reports ignored while one is unresolved

Stability:
- bootstrap only swallows the expected duplicate-column error; locked
  databases and schema failures now fail startup instead of the first
  endpoint
- clone blob write failure degrades to an empty sub-room instead of a
  500 after the clone row committed
- resumed photo-feed cursor stamped DateTimeKind.Utc (Npgsql rejects
  Unspecified for timestamptz)
- unreadcounts queries per requested room instead of materialising the
  whole comment keyspace

Tests:
- destroys-the-probe-session template guard is case-insensitive

74/74 tests pass.

DorkNet.Server/Controllers/API/Store/StorefrontsBuyController.cs

@@ -654,13 +654,28 @@ public class StorefrontsBuyController(
                 $"buyPurchaseReminder:{item.Slug}");
         var giftId = await GrantWithGiftBoxAsync(pid, item, currencyType);
 
-        db.ObjectiveProgress.Add(new ObjectiveProgressEntity
+        // Upsert: (PlayerId, Key) is unique and the same reminder can be
+        // bought again — a blind Add threw "UNIQUE constraint failed" and
+        // turned the second purchase into a 500 AFTER the currency had
+        // already been taken and the gift saved.
+        var progressKey = $"purchaseReminder:{req.PurchaseReminderId}";
+        var progress = await db.ObjectiveProgress
+            .FirstOrDefaultAsync(o => o.PlayerId == pid && o.Key == progressKey);
+        if (progress is null)
         {
-            PlayerId = pid,
-            Key = $"purchaseReminder:{req.PurchaseReminderId}",
-            IsCompleted = true,
-            ClearedAt = DateTime.UtcNow,
-        });
+            db.ObjectiveProgress.Add(new ObjectiveProgressEntity
+            {
+                PlayerId = pid,
+                Key = progressKey,
+                IsCompleted = true,
+                ClearedAt = DateTime.UtcNow,
+            });
+        }
+        else
+        {
+            progress.IsCompleted = true;
+            progress.ClearedAt = DateTime.UtcNow;
+        }
         await db.SaveChangesAsync();
 
         return Ok(PurchaseReminderResponse(newBalance, currencyType, item.Slug, giftId));