feat(skd-compile): horizontal cell merge ">" in template DSL

Add ">" cell syntax for horizontal merge (ОбъединятьПоГоризонтали),
analogous to "|" for vertical merge. Enables two-level headers with
colspan in DCS templates. Also fix PY decimal formatting (30.0 → 30).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/skills/cases/skd-compile/horizontal-merge.json

@@ -0,0 +1,47 @@
+{
+  "name": "Горизонтальное объединение ячеек (>) в шаблонах",
+  "params": { "outputPath": "Template.xml" },
+  "input": {
+    "dataSets": [{
+      "name": "Основной",
+      "query": "ВЫБРАТЬ Т.Счет, Т.Остаток, Т.Пост1, Т.Пост2, Т.Пост3, Т.Выб1, Т.Выб2, Т.Итого ИЗ Регистр КАК Т",
+      "fields": ["Счет: string", "Остаток: decimal(15,2)", "Пост1: decimal(15,2)", "Пост2: decimal(15,2)", "Пост3: decimal(15,2)", "Выб1: decimal(15,2)", "Выб2: decimal(15,2)", "Итого: decimal(15,2)"]
+    }],
+    "templates": [
+      {
+        "name": "Макет1",
+        "style": "header",
+        "widths": [30, 16, 16, 16, 16, 16, 16, 16],
+        "minHeight": 24.75,
+        "rows": [
+          ["Счет", "Остаток", "Поступление", ">", ">", "Выбытие", ">", "Итого"],
+          ["|", "|", "из произв.", "из п/ф", "прочее", "Реализ.", "прочее", "|"],
+          ["К1", "К2", "К3", "К4", "К5", "К6", "К7", "К8"]
+        ]
+      },
+      {
+        "name": "Макет2",
+        "style": "data",
+        "widths": [30, 16, 16, 16, 16, 16, 16, 16],
+        "rows": [["{Счет}", "{Остаток}", "{Пост1}", "{Пост2}", "{Пост3}", "{Выб1}", "{Выб2}", "{Итого}"]]
+      }
+    ],
+    "settingsVariants": [{
+      "name": "Основной",
+      "settings": {
+        "selection": ["Auto"],
+        "structure": "details"
+      }
+    }]
+  },
+  "validatePath": "Template.xml",
+  "expect": {
+    "files": ["Template.xml"],
+    "contains": [
+      "ОбъединятьПоГоризонтали",
+      "ОбъединятьПоВертикали",
+      "Поступление",
+      "Выбытие"
+    ]
+  }
+}