feat(shared): add poll and scheduled message RPC + collections (Phase 674)

Add COLLECTIONS.POLLS, POLL_VOTES, SCHEDULED_MESSAGES and RPC types for
guild-scoped poll/schedule mesh gossip so platform-global parity builds on
one shared contract.

index.js

@@ -30,6 +30,9 @@ const COLLECTIONS = {
   DM_CHANNEL_META: '@pearcord/dm-channel-meta',
   DM_POLLS: '@pearcord/dm-polls',
   DM_POLL_VOTES: '@pearcord/dm-poll-votes',
+  POLLS: '@pearcord/polls',
+  POLL_VOTES: '@pearcord/poll-votes',
+  SCHEDULED_MESSAGES: '@pearcord/scheduled-messages',
   USER_PREFS_MIRROR: '@pearcord/user-prefs-mirror',
   DM_CALL_HISTORY: '@pearcord/dm-call-history',
   VOICE_NOTES: '@pearcord/voice-notes'
@@ -493,7 +496,13 @@ const RPC = {
   /** DM voice call invite/accept/hangup on contacts mesh (Phase 656). */
   DM_VOICE_SIGNAL: 97,
   /** Voice message metadata after upload (Phase 662). */
-  VOICE_NOTE_CREATE: 98
+  VOICE_NOTE_CREATE: 98,
+  /** Guild/DM poll definition upsert (Phase 674). */
+  POLL_UPSERT: 99,
+  /** Guild/DM poll vote row (Phase 674). */
+  POLL_VOTE: 100,
+  /** Scheduled message metadata — body sent at fire time (Phase 674). */
+  SCHEDULED_MESSAGE_UPSERT: 101
 }
 
 const DEVICE_PAIR_PREFIX = 'pcdv_'