feat: add zCode Swarm — multi-agent orchestration system

- 6 agent skills: code-review, performance, security, architecture, test, git
- 4 coordinator modes: hierarchical, mesh, gossip, consensus
- Federated memory system (6 namespaces)
- Neural network agent recommendation
- Agent marketplace (plugin discovery/install)
- Real-time dashboard + performance metrics
- CRDT-based sync for decentralized modes
- 22 files, ~1400 lines total

Inspired by ruflo distributed multi-agent patterns.

.zcode/config/coordinator.yaml

@@ -0,0 +1,43 @@
+# zCode Swarm Configuration
+
+coordination:
+  mode: hierarchical  # hierarchical | mesh | gossip | consensus
+  timeout: 30000
+  retry_attempts: 3
+  fan_out: log2  # for mesh/gossip
+
+agents:
+  enabled:
+    - code-review-swarm
+    - performance-optimizer
+    - security-auditor
+    - architecture-analyzer
+    - test-orchestrator
+    - git-swarm
+  max_agents: 10
+  spawn_timeout: 10000
+
+performance:
+  metrics:
+    enabled: true
+    collection_interval: 60000
+    max_samples: 100
+
+dashboard:
+  enabled: false  # set true for terminal dashboard
+  update_interval: 5000
+
+neural:
+  enabled: true
+  model_type: neural-network
+  architecture: multi-layer-perceptron
+  layers: [64, 32, 16, 8]
+
+marketplace:
+  enabled: true
+  base_path: ./marketplace
+  install_path: ./installed
+
+memory:
+  retention_days: 30
+  max_entries_per_namespace: 10000