perf(brain): upgrade to 4 CPU / 4 GiB / 20 instances + rate limit WET injector

- Cloud Run: 2 CPU → 4 CPU, 2 GiB → 4 GiB, max 10 → 20 instances
- WET injector: 1s delay between batch injects to prevent brain saturation
- Deploy script updated to match new resource allocation

Co-Authored-By: claude-flow <ruv@ruv.net>

crates/mcp-brain-server/cloud/deploy-all.sh

@@ -34,10 +34,10 @@ gcloud run deploy ruvbrain \
   --region="$REGION" \
   --project="$PROJECT_ID" \
   --platform=managed \
-  --memory=2Gi \
-  --cpu=2 \
+  --memory=4Gi \
+  --cpu=4 \
   --min-instances=1 \
-  --max-instances=10 \
+  --max-instances=20 \
   --timeout=300 \
   --concurrency=80 \
   --session-affinity \

scripts/wet-filter-inject.js

@@ -222,9 +222,14 @@ function generateTags(url, content) {
   return [...new Set(tags)].slice(0, 10);
 }
 
+function sleep(ms) { return new Promise(r => setTimeout(r, ms)); }
+
 async function flushBatch() {
   if (batch.length === 0) return;
 
+  // Rate limit: 1 batch per second to avoid saturating the brain
+  await sleep(1000);
+
   const items = batch.splice(0);
   try {
     const res = await fetch(`${BRAIN_URL}/v1/pipeline/inject/batch`, {