feat(covenant): P3 - grant RenownRewards on covenant renown level-up

The covenant renown LEVEL is already a renown-reputation handled by TC's
ReputationMgr and synced to the client by the standard reputation packets,
so the only covenant-specific gap was granting the per-level rewards.

- Add the RenownRewards.db2 store (Meta 0x30AFBCF8, ParentIndex=CovenantID)
  and a DB2Manager (covenantId, level) -> rewards map (GetRenownRewards).
- Track the highest renown level whose rewards were granted, per covenant
  (Player::m_renownRewardsGranted), persisted to a new character_covenant_renown
  table and loaded at login, so each level's rewards are granted exactly once.
- Player::ReputationChanged now grants rewards for every renown level crossed
  when a covenant renown reputation increases; a login catch-up
  (UpdateAllRenownRewards, run in-world after SendInitialPacketsAfterAddToMap)
  grants anything earned before this feature existed. UpdateRenownRewards is
  guarded on IsInWorld() so nothing is granted mid-load.
- GrantRenownReward grants item / spell / title / mount via the existing
  Player + CollectionMgr APIs. The cosmetic-collection fields RenownRewards
  also carries (TransmogID/TransmogSetID/TransmogIllusionID, GarrFollowerID,
  QuestID) are documented as follow-ups rather than half-implemented.

sql/updates/characters/master/2026_07_08_00_characters.sql

@@ -0,0 +1,8 @@
+
+DROP TABLE IF EXISTS `character_covenant_renown`;
+CREATE TABLE `character_covenant_renown` (
+  `guid` bigint unsigned NOT NULL DEFAULT '0',
+  `covenantId` int unsigned NOT NULL DEFAULT '0',
+  `grantedLevel` int unsigned NOT NULL DEFAULT '0',
+  PRIMARY KEY (`guid`,`covenantId`)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci COMMENT='Highest covenant renown level whose rewards were granted';