v0.1.17: security hardening — 18/20 vulnerabilities fixed

Phase 1 (Critical):
- #1 JWT auth (done in v0.1.16)
- #2 Batch message size validation in send_message_batch.go
- #10 RLock in GetQueueUrlV1 (data race fix)

Phase 2 (AWS-compatible limits):
- #3 QueueName validation: max 80 chars, [a-zA-Z0-9_-](.fifo)?
- #4 WaitTimeSeconds clamped to 0-20
- #5 ReceiveMessageWaitTimeSeconds clamped to 0-20
- #6 DelaySeconds clamped to 0-900
- #7 VisibilityTimeout clamped to 0-43200
- #8 MaxNumberOfMessages clamped to 1-10
- #9 Message attributes limited to 10 per message
- #15 BatchEntryId length validated (max 80)
- #16 DeduplicationID length validated (max 128)
- #17 GroupID length validated (max 128)

Phase 3 (Per-tenant resource limits):
- #11 Max messages per queue (120K standard, 20K FIFO)
- #12 Global tenant limit (1000)
- #3.5 HTTP request body size limit (1MB via MaxBytesReader)

Phase 4 (Stability):
- #14 Duplicates map cleanup (already in PeriodicTasks)
- #13 FIFO group lock timeout (already in visibility timeout reset)
- #18 Redis size guard: skip save if >50MB

Skipped (Low, no real risk):
- #19 {account} URL param (informational only, not used for access)
- #20 ReceiptHandle format (self-validating UUID#UUID)

New file: app/gosqs/validation.go — centralized AWS SQS limits and validators

app/gosqs/receive_message.go

@@ -35,6 +35,8 @@ maxNumberOfMessages := requestBody.MaxNumberOfMessages
 if maxNumberOfMessages == 0 {
 maxNumberOfMessages = 1
 }
+// Fix #8: clamp MaxNumberOfMessages к AWS лимиту 1–10
+maxNumberOfMessages = ClampInt(maxNumberOfMessages, MinNumberOfMessagesLimit, MaxNumberOfMessagesLimit)
 
 queueName := ""
 if requestBody.QueueUrl == "" {
@@ -60,6 +62,8 @@ models.SyncQueues.RLock()
 waitTimeSeconds = models.SyncQueues.Queues[key].ReceiveMessageWaitTimeSeconds
 models.SyncQueues.RUnlock()
 }
+// Fix #4: clamp WaitTimeSeconds к AWS лимиту 0–20
+waitTimeSeconds = ClampInt(waitTimeSeconds, 0, MaxReceiveMessageWaitTimeSeconds)
 
 // Long polling: ждём появления сообщения до waitTimeSeconds*10 итераций по 100ms
 loops := waitTimeSeconds * 10