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/Accounts/AccountsController.cs

@@ -1,3 +1,4 @@
+using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.EntityFrameworkCore;
 using DorkNet.Models.Auth;
@@ -808,8 +809,12 @@ public class AccountsController(
     /// Unknown accounts get an empty string — "no platform identity" is the
     /// honest answer and keeps the promise resolved rather than rejected.
     /// </summary>
+    // LastPlatformId is a third-party identifier (Steam/Oculus id); without
+    // an auth gate this was an anonymous enumeration oracle over every
+    // account. The 2023 client only ever calls it with a token.
     [HttpGet("/platformid/{accountId:long}")]
     [HttpGet("/account/v1/{accountId:long}/platformid")]
+    [Authorize]
     public async Task<IActionResult> GetPlatformId(long accountId)
     {
         var platformId = await db.Players