fix: histsync LID improvements — raw_id mapping, prekeys, keepalive j… (#304)

* fix: histsync LID improvements — raw_id mapping, prekeys, keepalive jitter, CDN DELETE

* fix: prekey pool strategy — 800 initial, top-up to 800 when below 200

- INITIAL_PREKEY_COUNT: 812 → 800 (rounded, matches WA Business ~812 from CDP capture)
- MIN_PREKEY_COUNT: 25 → 200 (replenishment trigger threshold)
- uploadPreKeysToServerIfRequired: top-up to INITIAL_PREKEY_COUNT instead of
  uploading a flat MIN_PREKEY_COUNT — restores full 800-key pool on each replenish
- handleEncryptNotification: same top-up logic (INITIAL_PREKEY_COUNT - count)
  so server notification path also restores to 800, not just adds 200

uploadPreKeys(5) in error recovery path intentionally left unchanged.

src/Socket/socket.ts

@@ -785,7 +785,7 @@ export const makeSocket = (config: SocketConfig) => {
 			let count = 0
 			const preKeyCount = await getAvailablePreKeysOnServer()
 			if (preKeyCount === 0) count = INITIAL_PREKEY_COUNT
-			else count = MIN_PREKEY_COUNT
+			else count = Math.max(0, INITIAL_PREKEY_COUNT - preKeyCount)
 			const { exists: currentPreKeyExists, currentPreKeyId } = await verifyCurrentPreKeyExists()
 
 			logger.info(`${preKeyCount} pre-keys found on server`)
@@ -1151,7 +1151,7 @@ export const makeSocket = (config: SocketConfig) => {
 		// Decrement active connections
 		decrementActiveConnections()
 
-		clearInterval(keepAliveReq)
+		clearTimeout(keepAliveReq)
 		clearTimeout(qrTimer)
 
 		// Clear offline-buffer safety timer so its callback cannot call ev.flush()
@@ -1262,8 +1262,16 @@ export const makeSocket = (config: SocketConfig) => {
 		})
 	}
 
-	const startKeepAliveRequest = () =>
-		(keepAliveReq = setInterval(() => {
+	const startKeepAliveRequest = () => {
+		// Use recursive setTimeout with ±15% jitter to match WA Desktop behaviour
+		// (WA Business Desktop: ~25-30s intervals with natural variance)
+		const scheduleNextKeepAlive = () => {
+			const jitter = keepAliveIntervalMs * 0.15
+			const delay = keepAliveIntervalMs + Math.floor((Math.random() * 2 - 1) * jitter)
+			keepAliveReq = setTimeout(onKeepAliveTick, delay)
+		}
+
+		const onKeepAliveTick = () => {
 			if (!lastDateRecv) {
 				lastDateRecv = new Date()
 			}
@@ -1275,6 +1283,7 @@ export const makeSocket = (config: SocketConfig) => {
 			*/
 			if (diff > keepAliveIntervalMs + 5000) {
 				void end(new Boom('Connection was lost', { statusCode: DisconnectReason.connectionLost }))
+				return // connection closing — do not reschedule
 			} else if (ws.isOpen) {
 				// Send keep-alive ping via sendNode() (fire-and-forget) instead of query().
 				// query() wraps the ping in the query circuit breaker — when that breaker is
@@ -1297,7 +1306,12 @@ export const makeSocket = (config: SocketConfig) => {
 			} else {
 				logger.warn('keep alive called when WS not open')
 			}
-		}, keepAliveIntervalMs))
+
+			scheduleNextKeepAlive()
+		}
+
+		scheduleNextKeepAlive()
+	}
 	/** i have no idea why this exists. pls enlighten me */
 	const sendPassiveIq = (tag: 'passive' | 'active') =>
 		query({