[add]: Database health check

app/swagger/digifi_swagger.json

@@ -83,6 +83,10 @@
         "description": "Find out more",
         "url": "https://www.simbrellang.net"
       }
+    },
+    {
+      "name": "Health",
+      "description": "System health check including DB status."
     }
   ],
   "paths": {
@@ -106,6 +110,38 @@
     },
     "/Repayment": {
       "$ref": "swagger/paths/Repayment.json"
+    },
+    "/health": {
+      "get": {
+        "tags": ["Health"],
+        "summary": "Health Check",
+        "description": "Returns service health information including DB connection status.",
+        "responses": {
+          "200": {
+            "description": "Health check successful",
+            "content": {
+              "application/json": {
+                "example": {
+                  "status": "ok",
+                  "db_status": "Connection Successful"
+                }
+              }
+            }
+          },
+          "500": {
+            "description": "Health check failed",
+            "content": {
+              "application/json": {
+                "example": {
+                  "status": "ok",
+                  "db_status": "Connection Failed",
+                  "error": "could not connect to server: Connection refused"
+                }
+              }
+            }
+          }
+        }
+      }
     }
   },
   "components": {