DOC-3498: Clean up architecture overview diagram

Reduce edge clutter by connecting a single representative replica
to downstream services and grouping the data layer into a subgraph.
Fix SVG width to use a fixed pixel value consistent with other
diagrams in the set.

Author: kemister85

modules/ROOT/images/tinymceai-on-premises/complete-guide-fig-1.mmd

@@ -6,37 +6,23 @@ flowchart TB
 
     subgraph App["Application layer (stateless, N replicas)"]
         LB["Reverse proxy / Load balancer<br>nginx · ALB · K8s Ingress<br>TLS termination · SSE pass-through"]
-        AI1["ai-service replica 1"]
-        AI2["ai-service replica 2"]
         AIN["ai-service replica N"]
-        LB --> AI1
-        LB --> AI2
+        AI2["ai-service replica 2"]
+        AI1["ai-service replica 1"]
         LB --> AIN
+        LB --> AI2
+        LB --> AI1
     end
 
     subgraph Data["Shared data layer"]
-        DB[("SQL database<br>MySQL 8.0+ or<br>PostgreSQL 13+")]
-        Cache[("Redis 3.2.6+<br>single node or cluster")]
-        Storage[("File storage<br>database · filesystem ·<br>S3 · Azure Blob")]
+        DB[("SQL database<br>MySQL 8.0+ / PostgreSQL 13+")]
+        Cache[("Redis 3.2.6+")]
+        Storage[("File storage<br>S3 · Azure Blob · filesystem")]
     end
 
-    AI1 --> DB
-    AI1 --> Cache
-    AI1 --> Storage
-    AI2 --> DB
-    AI2 --> Cache
-    AI2 --> Storage
-    AIN --> DB
-    AIN --> Cache
-    AIN --> Storage
-
-    AI1 -->|HTTPS| LLM["LLM provider<br>OpenAI · Anthropic · Google ·<br>Azure · Bedrock · Vertex · self-hosted"]
-    AI2 -->|HTTPS| LLM
-    AIN -->|HTTPS| LLM
+    AI1 --> Data
 
-    AI1 -.-> Obs["OpenTelemetry · Langfuse ·<br>log aggregator"]
-    AI2 -.-> Obs
-    AIN -.-> Obs
+    AI1 -->|"HTTPS"| LLM["LLM provider<br>OpenAI · Anthropic · Google ·<br>Azure · Bedrock · Vertex ·<br>self-hosted"]
 
-    AI1 -.->|tool calls| MCP["MCP servers<br>internal knowledge bases"]
-    AI2 -.-> MCP
+    AI1 -.->|"telemetry"| Obs["OpenTelemetry · Langfuse"]
+    AI1 -.->|"tool calls"| MCP["MCP servers"]