Normalise route naming scheme to 'Route X (Region)' format

Standardise 426 inconsistent route names across 33 seed data files
(game data + boss files). Converts 'Region Route X' prefix style and
'Route X - Region' dash style to the consistent 'Route X (Region)' format.

Resolves beans-r48e.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/src/app/seeds/data/diamond.json

@@ -747,7 +747,7 @@
     ]
   },
   {
-    "name": "Sinnoh Route 204",
+    "name": "Route 204 (Sinnoh)",
     "order": 12,
     "encounters": [],
     "children": [
@@ -1108,7 +1108,7 @@
     ]
   },
   {
-    "name": "Sinnoh Route 205",
+    "name": "Route 205 (Sinnoh)",
     "order": 16,
     "encounters": [],
     "children": [
@@ -3787,7 +3787,7 @@
     ]
   },
   {
-    "name": "Sinnoh Route 210",
+    "name": "Route 210 (Sinnoh)",
     "order": 64,
     "encounters": [],
     "children": [
@@ -5344,7 +5344,7 @@
     ]
   },
   {
-    "name": "Sinnoh Route 212",
+    "name": "Route 212 (Sinnoh)",
     "order": 79,
     "encounters": [],
     "children": [
@@ -6596,7 +6596,7 @@
     ]
   },
   {
-    "name": "Sinnoh Route 211",
+    "name": "Route 211 (Sinnoh)",
     "order": 94,
     "encounters": [],
     "children": [
@@ -8028,7 +8028,7 @@
     ]
   },
   {
-    "name": "Pok\u00e9mon League (Sinnoh)",
+    "name": "Pokémon League (Sinnoh)",
     "order": 115,
     "encounters": [
       {