Add settings mesh RPC methods for multi-device sync health.

GUILD_SYNC_HEALTH (94) and SETTINGS_READ_RECEIPT_SYNC (95) support guild
sync health gossip and cross-device read receipt merge on the settings topic.

Co-authored-by: Cursor <[email protected]>

README.md

@@ -27,7 +27,7 @@ Provide a single source of truth for HyperDB collection names, channel and membe
 | `COLLECTIONS` | HyperDB / JSON collection keys (`@pearcord/users`, …) |
 | `CHANNEL_TYPES`, `USER_STATUS`, `MEMBER_ROLES` | Domain enums |
 
-**v0.8.421:** `RPC.CHANNEL_DELETE` (85) for P2P channel removal gossip.
+**v0.8.611 (Phase 639):** `RPC.GUILD_SYNC_HEALTH` (94) and `RPC.SETTINGS_READ_RECEIPT_SYNC` (95) for multi-device settings mesh health + read receipt gossip.
 | `PERMISSION`, `ROLE_PERMISSIONS` | Bitmask permission model |
 | `memberCanParticipate`, `memberCanViewChannel`, `memberCanConnectVoice`, `memberCanSpeakInVoice`, `memberCanJoinVoiceListenOnly` | Effective-mask aware checks |
 | `memberHasPermission`, `roleHasPermission`, `canModifyMessage` | Moderation / edit rules |

index.js

@@ -304,7 +304,11 @@ const RPC = {
   /** Joiner requests paged member roster slice (large guilds). */
   MEMBER_PAGE_REQUEST: 92,
   /** Owner/mod responds with member page + user profiles. */
-  MEMBER_PAGE: 93
+  MEMBER_PAGE: 93,
+  /** Multi-device guild sync health snapshot on settings mesh. */
+  GUILD_SYNC_HEALTH: 94,
+  /** Cross-device read receipt vector row on settings mesh. */
+  SETTINGS_READ_RECEIPT_SYNC: 95
 }
 
 const DEVICE_PAIR_PREFIX = 'pcdv_'