n8n: raise memory 512M -> 1536M (V8 heap OOM proven during validation)

n8n 2.31.3 died on a fresh deploy under the 512M limit:

  FATAL ERROR: Ineffective mark-compacts near heap limit
  Allocation failed - JavaScript heap out of memory

Note the container still reported *healthy* while the Node process was crashing,
so docker health alone did not catch this -- the log scan did.

Campaign 7 catalog sweep.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Nn3VgQk9iwEGgyx6QJ2NvE

templates/n8n/docker-compose.yml

@@ -25,7 +25,7 @@ services:
     deploy:
       resources:
         limits:
-          memory: 512M
+          memory: 1536M
     healthcheck:
       test: ["CMD", "wget", "--spider", "-q", "http://127.0.0.1:5678/healthz"]
       interval: 30s