Rework network to 6-tier Clos topology with individual switch entities

Replace aggregate network health stats with a full 6-tier Clos topology
(ToR → T1 → T2 → T3 → T4 → T5) where every switch is an individually
tracked entity with uplinks, repair pipelines, and failure cascades.

Key mechanics:
- Bottleneck bandwidth model (min along path) affects FLOPS and satisfaction
- Rackdown on full disconnect → racks re-enter testing pipeline on recovery
- Binomial failure sampling per tier, dirty-flag cascade optimization
- Flat switch registry for performance at scale
- Three new research nodes: network-redundancy, fast-repair, hot-standby

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/game-engine/src/data/techTree.ts

@@ -122,6 +122,36 @@ export const TECH_TREE: ResearchNode[] = [
     cost: { researchPoints: 4, compute: 80, ticks: 360 },
     effects: [{ type: 'cost_reduction', target: 'network_failure_rate', value: 0.5 }],
   },
+  {
+    id: 'network-redundancy',
+    name: 'Network Redundancy',
+    description: 'Additional uplink per switch at all tiers — reduces disconnect risk from single switch failures.',
+    era: 'scaleup',
+    category: 'infrastructure',
+    prerequisites: ['network-engineering-i'],
+    cost: { researchPoints: 3, compute: 40, ticks: 240 },
+    effects: [{ type: 'efficiency_boost', target: 'network_uplinks', value: 1 }],
+  },
+  {
+    id: 'network-fast-repair',
+    name: 'Fast Network Repair',
+    description: 'Hot-swap switch modules and pre-staged spares reduce network repair time by 40%.',
+    era: 'bigtech',
+    category: 'infrastructure',
+    prerequisites: ['network-engineering-ii'],
+    cost: { researchPoints: 5, compute: 100, ticks: 400 },
+    effects: [{ type: 'efficiency_boost', target: 'network_repair_speed', value: 0.4 }],
+  },
+  {
+    id: 'network-hot-standby',
+    name: 'Hot Standby Switches',
+    description: 'Automated failover with standby switches — failed switches auto-replace in 5 ticks.',
+    era: 'agi',
+    category: 'infrastructure',
+    prerequisites: ['network-fast-repair'],
+    cost: { researchPoints: 8, compute: 250, ticks: 600 },
+    effects: [{ type: 'efficiency_boost', target: 'network_hot_standby', value: 5 }],
+  },
   {
     id: 'rapid-deployment',
     name: 'Rapid Deployment',