fix(emergency): drastically lower high-volume mode activation thresholds

EMERGENCY FIX for bluesky-package socket exhaustion despite v0.54.1

🚨 CRITICAL CHANGES:
- Activation threshold: 100 → 1 pending operation (configurable)
- Add socket utilization trigger: >10% usage activates buffering
- Add environment variables:
  - BRAINY_BUFFER_THRESHOLD=1 (when to start buffering)
  - BRAINY_FORCE_BUFFERING=true (force enable)
- Add comprehensive logging with emojis for visibility:
  - '🚨 HIGH-VOLUME MODE ACTIVATED 🚨' when buffering starts
  - '🚀 BATCH FLUSH: N items → 1 bulk S3 operation' for batch writes
  - '📈 BUFFER GROWTH: N items buffered' every 100 additions

PROBLEM: v0.54.1 buffering not activating with 7,500 pending requests
SOLUTION: Activate buffering at first sign of load (1+ pending operations)

This should immediately activate buffering in bluesky-package production.

tests/emergency-high-volume-test.js

@@ -0,0 +1,81 @@
+/**
+ * Emergency test to verify high-volume buffering activates correctly
+ * Simulates the exact bluesky-package scenario
+ */
+
+const { BrainyData } = await import('../dist/index.js')
+
+console.log('🧪 Testing high-volume buffering activation...')
+
+// Create Brainy with memory storage for testing
+const brainy = new BrainyData({
+  dimensions: 384,
+  storage: { 
+    type: 'memory' 
+  }
+})
+
+console.log('📊 Starting rapid fire operations (simulating bluesky firehose)...')
+
+// Simulate the exact pattern that's failing
+let operationCount = 0
+const startTime = Date.now()
+
+// Fire off 1000 operations without awaiting (like bluesky firehose)
+const promises = []
+for (let i = 0; i < 1000; i++) {
+  const promise = brainy.add({
+    id: `firehose-${i}`,
+    data: {
+      type: 'bluesky_post',
+      content: `Message ${i} from firehose`,
+      timestamp: Date.now()
+    },
+    metadata: {
+      source: 'bluesky',
+      batch: Math.floor(i / 100)
+    }
+  }).catch(error => {
+    console.error(`Failed to add item ${i}:`, error.message)
+    return null
+  })
+  
+  promises.push(promise)
+  operationCount++
+  
+  // Log every 100 operations
+  if (i > 0 && i % 100 === 0) {
+    console.log(`📈 Fired ${i} operations (not awaited)`)
+    // Small delay to allow buffer detection
+    await new Promise(resolve => setTimeout(resolve, 10))
+  }
+}
+
+console.log(`🚀 All ${operationCount} operations fired! Now waiting for completion...`)
+
+// Wait for all operations to complete
+const results = await Promise.all(promises)
+const successful = results.filter(r => r !== null).length
+const failed = results.filter(r => r === null).length
+
+const duration = Date.now() - startTime
+console.log(`\n✅ Test completed in ${duration}ms`)
+console.log(`   Successful: ${successful}/${operationCount}`)
+console.log(`   Failed: ${failed}/${operationCount}`)
+
+if (successful < operationCount * 0.9) {
+  console.error('❌ Test failed - too many operations failed')
+  process.exit(1)
+} else {
+  console.log('✅ Test passed - high-volume operations completed successfully')
+}
+
+// Check if we have data
+const searchResults = await brainy.search('bluesky', { k: 5 })
+console.log(`🔍 Search results: ${searchResults.length} items found`)
+
+console.log('\n🎯 Key things to check in logs:')
+console.log('   1. "🚨 HIGH-VOLUME MODE ACTIVATED 🚨" message')
+console.log('   2. "📝 BUFFERING: Adding noun/verb to write buffer" messages') 
+console.log('   3. "🚀 BATCH FLUSH:" messages showing bulk operations')
+console.log('   4. "📈 BUFFER GROWTH:" messages showing buffer accumulation')