improve: add warning logs to null guards and fix transferDevice error handling

- Add warning/debug logs to all null guard patterns (if (!x) return/continue)
  so that when these guards fire, the reason is visible in logs instead of
  being silently swallowed
- Fix jid-utils.ts transferDevice: throw Error instead of returning empty
  string '' which could propagate as an invalid JID
- process-message.ts: warn on creds.me missing, reactionKey missing,
  creationMsgKey missing, eventCreatorPn missing
- chats.ts: warn on sendPresenceUpdate/handlePresenceUpdate missing values
- event-buffer.ts: debug on chat/contact/group update missing id
- socket.ts: debug on sessionStartTime not set
- communities.ts: debug on dirty node not found
- libsignal.ts: warn on bulk migration jidDecode failure

https://claude.ai/code/session_01XaA7GwNaB6azTHFYQ8WEpB

src/Socket/chats.ts

@@ -754,9 +754,16 @@ export const makeChatsSocket = (config: SocketConfig) => {
 				})
 			}
 		} else {
-			if (!toJid) return
+			if (!toJid) {
+				logger.warn('sendPresenceUpdate: toJid is missing, skipping')
+				return
+			}
+
 			const decoded = jidDecode(toJid)
-			if (!decoded) return
+			if (!decoded) {
+				logger.warn({ toJid }, 'sendPresenceUpdate: failed to decode toJid, skipping')
+				return
+			}
 			const { server } = decoded
 			const isLid = server === 'lid'
 
@@ -798,7 +805,10 @@ export const makeChatsSocket = (config: SocketConfig) => {
 		let presence: PresenceData | undefined
 		const jid = attrs.from
 		const participant = attrs.participant || attrs.from
-		if (!jid) return
+		if (!jid) {
+			logger.warn({ attrs }, 'handlePresenceUpdate: jid (attrs.from) is missing, skipping')
+			return
+		}
 
 		if (shouldIgnoreJid(jid) && jid !== S_WHATSAPP_NET) {
 			return
@@ -811,7 +821,10 @@ export const makeChatsSocket = (config: SocketConfig) => {
 			}
 		} else if (Array.isArray(content)) {
 			const [firstChild] = content
-			if (!firstChild) return
+			if (!firstChild) {
+				logger.warn({ jid }, 'handlePresenceUpdate: firstChild content is empty, skipping')
+				return
+			}
 			let type = firstChild.tag as WAPresence
 			if (type === 'paused') {
 				type = 'available'
@@ -827,7 +840,11 @@ export const makeChatsSocket = (config: SocketConfig) => {
 		}
 
 		if (presence) {
-			if (!participant) return
+			if (!participant) {
+				logger.warn({ jid }, 'handlePresenceUpdate: participant is missing, skipping')
+				return
+			}
+
 			ev.emit('presence.update', { id: jid, presences: { [participant]: presence } })
 		}
 	}

src/Socket/communities.ts

@@ -102,6 +102,7 @@ export const makeCommunitiesSocket = (config: SocketConfig) => {
 	sock.ws.on('CB:ib,,dirty', async (node: BinaryNode) => {
 		const dirtyNode = getBinaryNodeChild(node, 'dirty')
 		if (!dirtyNode) {
+			logger.debug({ node: node.tag }, 'community dirty handler: no dirty node found, skipping')
 			return
 		}
 

src/Socket/socket.ts

@@ -886,6 +886,7 @@ export const makeSocket = (config: SocketConfig) => {
 					}
 
 					if (!sessionStartTime) {
+						logger.debug('TTL timer: sessionStartTime not set, skipping')
 						return
 					}