feat: update documentation with project details, deployment instructions, and database concurrency management

Co-authored-by: Copilot <copilot@github.com>

docs/5-building-block-view.md

@@ -5,21 +5,21 @@ Static decomposition of the system into building blocks (modules, components, su
 ## Level 1 – Whitebox Overall System
 
 ```text
-┌───────────────────────┐
-│  Frontend (Flask)     │
-└───────┬───────────────┘
+┌────────────────────────┐
+│  Frontend (Flask)      │
+└───────┬────────────────┘
         │ REST API calls
-┌───────▼───────────────┐
-│  FastAPI Backend      │
-│  ├─ Auth Service      │
-│  ├─ User Service      │
-│  ├─ AI Service        │
+┌───────▼────────────────┐
+│  FastAPI Backend       │
+│  ├─ Auth Service       │
+│  ├─ User Service       │
+│  ├─ AI Service         │
 │  └─ DB Service (DuckDB)│
-└───────┬───────────────┘
+└───────┬────────────────┘
         │ DB access
-┌───────▼───────────────┐
-│  DuckDB Database      │
-└───────────────────────┘
+┌───────▼────────────────┐
+│  DuckDB Database       │
+└────────────────────────┘
 ```
 
 **Motivation:** Separating the UI (Flask) from the API (FastAPI) allows independent scaling and testing of each layer.