docs(README): Use subgraph LR

Makes it more readable

README.md

@@ -39,7 +39,7 @@ The generator currently supports problems related to the following topics (align
 The problem generator is a modular system composed of several Python scripts and JSON data files that work together to produce financial problems.
 
 ```mermaid
-graph TD
+graph LR
     A[problem_engine.py] --> B(data_loader.py);
     A --> C(value_sampler.py);
     A --> D(date_utils.py);
@@ -47,18 +47,18 @@ graph TD
     A --> F(narrative_builder.py);
     A --> G(solution_presenter.py);
 
-    B -- Reads & Caches --> H[financial_concepts.json];
-    B -- Reads & Caches --> I[value_ranges.json];
-    B -- Reads & Caches --> J[text_snippets.json];
-    B -- Reads & Caches --> K[data/names.json];
+    B -- "Reads & Caches" --> H["financial_concepts.json"];
+    B -- "Reads & Caches" --> I["value_ranges.json"];
+    B -- "Reads & Caches" --> J["text_snippets.json"];
+    B -- "Reads & Caches" --> K["data/names.json"];
 
-    C -- Uses Constraints From --> I;
-    C -- Uses Date Functions From --> D;
-    F -- Uses Actor Names From --> K;
-    F -- Uses Text Templates From --> J;
-    G -- Uses Text Templates From --> J;
+    C -- "Uses Constraints From" --> I;
+    C -- "Uses Date Functions From" --> D;
+    F -- "Uses Actor Names From" --> K;
+    F -- "Uses Text Templates From" --> J;
+    G -- "Uses Text Templates From" --> J;
 
-    subgraph Python Modules
+    subgraph "Python Modules"
         A
         B
         C
@@ -68,11 +68,11 @@ graph TD
         G
     end
 
-    subgraph Data Files (JSON)
-        H[building_blocks/financial_concepts.json]
-        I[data/value_ranges.json]
-        J[data/text_snippets.json]
-        K[data/names.json]
+    subgraph "Data Files (JSON)"
+        H["building_blocks/financial_concepts.json"]
+        I["data/value_ranges.json"]
+        J["data/text_snippets.json"]
+        K["data/names.json"]
     end
 ```