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.

src/utils/writeBuffer.ts

@@ -31,10 +31,10 @@ export class WriteBuffer<T> {
   // Buffer storage
   private buffer = new Map<string, BufferedWrite<T>>()
   
-  // Configuration
-  private maxBufferSize = 1000      // Maximum items before forced flush
-  private flushInterval = 1000      // Flush every second
-  private minFlushSize = 100        // Minimum items to flush (unless timeout)
+  // Configuration - More aggressive for high volume
+  private maxBufferSize = 2000      // Allow larger buffers
+  private flushInterval = 500       // Flush more frequently (0.5 seconds)
+  private minFlushSize = 50         // Lower minimum to flush sooner
   private maxRetries = 3            // Maximum retry attempts
   
   // State
@@ -115,6 +115,11 @@ export class WriteBuffer<T> {
     
     this.totalWrites++
     
+    // Log buffer growth periodically
+    if (this.totalWrites % 100 === 0) {
+      this.logger.info(`📈 BUFFER GROWTH: ${this.buffer.size} ${this.type} items buffered (${this.totalWrites} total writes, ${this.duplicatesRemoved} deduplicated)`)
+    }
+    
     // Check if we should flush
     this.checkFlush()
   }
@@ -203,7 +208,7 @@ export class WriteBuffer<T> {
       this.buffer.delete(id)
     }
     
-    this.logger.debug(`Flushing ${itemsToFlush.size} ${this.type} items - reason: ${reason}`)
+    this.logger.warn(`🔄 BUFFERING: Flushing ${itemsToFlush.size} ${this.type} items (buffer had ${this.buffer.size + itemsToFlush.size}) - reason: ${reason}`)
     
     try {
       // Request permission from backpressure system
@@ -220,7 +225,7 @@ export class WriteBuffer<T> {
         this.lastFlush = Date.now()
         
         const duration = Date.now() - startTime
-        this.logger.info(`Flushed ${itemsToFlush.size} items in ${duration}ms`)
+        this.logger.warn(`🚀 BATCH FLUSH: ${itemsToFlush.size} ${this.type} items → 1 bulk S3 operation (${duration}ms, reason: ${reason})`)
         
         return {
           successful: itemsToFlush.size,