refactor(backend): reorder Program.cs sections into reads-then-writes (RB-19)

CQ-006 found that Program.cs states a reads-then-writes principle at the
top of the file, then abandons it for five feature sections that mix GET
and mutating endpoints in mapping order. This is a pure reorder: within
Document upload, Applications, Admin cases, Brief, and Organization
templates, every GET now precedes every POST/PUT/DELETE, each split by a
`--- reads ---`/`--- writes ---` sub-banner in the style WP-65 already
established for Beoordeling/Besluit.

DELETE /admin/cases/{id} and GET /admin/audit move up beside GET
/admin/cases, closing the 129-line gap CQ-006 measured. GET
/admin/org-template/{subOrgId}/preview moves from the Brief section to
the Organization-templates section it actually belongs to.

No route, signature, DTO, or handler body changed. Every block was cut
by exact line-range slicing, never retyped. The sorted list of mapped
HTTP-method-plus-path strings is byte-identical before and after; every
.Gate(...) count is unchanged; the three routes that moved with a gate
were checked by eye against the wrapper their handler actually calls,
per RB-12's stated limitation that the route-table test only proves a
marker is present, not that it still matches the handler.

npm run gen:api regenerated backend/swagger.json and
libs/shared/src/infrastructure/api-client.ts; both diffs are ordering
only (sorted-file diff is empty), committed alongside per the ticket's
own guidance.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

backend/swagger.json

@@ -686,6 +686,73 @@
         }
       }
     },
+    "/api/v1/admin/audit": {
+      "get": {
+        "tags": [
+          "BigRegister.Api, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null"
+        ],
+        "responses": {
+          "200": {
+            "description": "OK",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "type": "array",
+                  "items": {
+                    "$ref": "#/components/schemas/AuthzAuditDto"
+                  }
+                }
+              }
+            }
+          },
+          "403": {
+            "description": "Forbidden",
+            "content": {
+              "application/problem+json": {
+                "schema": {
+                  "$ref": "#/components/schemas/ProblemDetails"
+                }
+              }
+            }
+          }
+        }
+      }
+    },
+    "/api/v1/admin/cases/{id}": {
+      "delete": {
+        "tags": [
+          "BigRegister.Api, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null"
+        ],
+        "parameters": [
+          {
+            "name": "id",
+            "in": "path",
+            "required": true,
+            "schema": {
+              "type": "string"
+            }
+          }
+        ],
+        "responses": {
+          "204": {
+            "description": "No Content"
+          },
+          "404": {
+            "description": "Not Found"
+          },
+          "403": {
+            "description": "Forbidden",
+            "content": {
+              "application/problem+json": {
+                "schema": {
+                  "$ref": "#/components/schemas/ProblemDetails"
+                }
+              }
+            }
+          }
+        }
+      }
+    },
     "/api/v1/werkvoorraad": {
       "get": {
         "tags": [
@@ -832,73 +899,6 @@
         }
       }
     },
-    "/api/v1/admin/cases/{id}": {
-      "delete": {
-        "tags": [
-          "BigRegister.Api, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null"
-        ],
-        "parameters": [
-          {
-            "name": "id",
-            "in": "path",
-            "required": true,
-            "schema": {
-              "type": "string"
-            }
-          }
-        ],
-        "responses": {
-          "204": {
-            "description": "No Content"
-          },
-          "404": {
-            "description": "Not Found"
-          },
-          "403": {
-            "description": "Forbidden",
-            "content": {
-              "application/problem+json": {
-                "schema": {
-                  "$ref": "#/components/schemas/ProblemDetails"
-                }
-              }
-            }
-          }
-        }
-      }
-    },
-    "/api/v1/admin/audit": {
-      "get": {
-        "tags": [
-          "BigRegister.Api, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null"
-        ],
-        "responses": {
-          "200": {
-            "description": "OK",
-            "content": {
-              "application/json": {
-                "schema": {
-                  "type": "array",
-                  "items": {
-                    "$ref": "#/components/schemas/AuthzAuditDto"
-                  }
-                }
-              }
-            }
-          },
-          "403": {
-            "description": "Forbidden",
-            "content": {
-              "application/problem+json": {
-                "schema": {
-                  "$ref": "#/components/schemas/ProblemDetails"
-                }
-              }
-            }
-          }
-        }
-      }
-    },
     "/api/v1/me": {
       "get": {
         "tags": [