fix(kg): 修复知识图谱部署流程问题

修复从全新部署到运行的完整流程中的配置和路由问题。

## P0 修复（功能失效）

### P0-1: GraphRAG KG 服务 URL 错误
- config.py - GRAPHRAG_KG_SERVICE_URL 从 http://datamate-kg:8080 改为 http://datamate-backend:8080（容器名修正）
- kg_client.py - 修复 API 路径：/knowledge-graph/... → /api/knowledge-graph/...
- kb_access.py - 同类问题修复：/knowledge-base/... → /api/knowledge-base/...
- test_kb_access.py - 测试断言同步更新

根因：容器名 datamate-kg 不存在，且 httpx 绝对路径会丢弃 base_url 中的 /api 路径

### P0-2: Vite 开发代理剥离 /api 前缀
- vite.config.ts - 删除 /api/knowledge-graph 专用代理规则（剥离 /api 导致 404），统一走 ^/api 规则

## P1 修复（功能受损）

### P1-1: Gateway 缺少 KG Python 端点路由
- ApiGatewayApplication.java - 添加 /api/kg/** 路由（指向 kg-extraction Python 服务）
- ApiGatewayApplication.java - 添加 /api/graphrag/** 路由（指向 GraphRAG 服务）

### P1-2: DATA_MANAGEMENT_URL 默认值缺 /api
- KnowledgeGraphProperties.java - dataManagementUrl 默认值 http://localhost:8080 → http://localhost:8080/api
- KnowledgeGraphProperties.java - annotationServiceUrl 默认值 http://localhost:8081 → http://localhost:8080/api（同 JVM）
- application-knowledgegraph.yml - YAML 默认值同步更新

### P1-3: Neo4j k8s 安装链路失败
- Makefile - VALID_K8S_TARGETS 添加 neo4j
- Makefile - %-k8s-install 添加 neo4j case（显式 skip，提示使用 Docker 或外部实例）
- Makefile - %-k8s-uninstall 添加 neo4j case（显式 skip）

根因：install 目标无条件调用 neo4j-$(INSTALLER)-install，但 k8s 模式下 neo4j 不在 VALID_K8S_TARGETS 中，导致 "Unknown k8s target 'neo4j'" 错误

## P2 修复（次要）

### P2-1: Neo4j 加入 Docker install 流程
- Makefile - install target 增加 neo4j-$(INSTALLER)-install，在 datamate 之前启动
- Makefile - VALID_SERVICE_TARGETS 增加 neo4j
- Makefile - %-docker-install / %-docker-uninstall 增加 neo4j case

## 验证结果
- mvn test: 311 tests, 0 failures ✅
- eslint: 0 errors ✅
- tsc --noEmit: 通过 ✅
- vite build: 成功 (17.71s) ✅
- Python tests: 46 passed ✅
- make -n install INSTALLER=k8s: 不再报 unknown target ✅
- make -n neo4j-k8s-install: 正确显示 skip 消息 ✅

runtime/datamate-python/app/core/config.py

@@ -91,7 +91,7 @@ class Settings(BaseSettings):
     # GraphRAG 融合查询配置
     graphrag_enabled: bool = False
     graphrag_milvus_uri: str = "http://milvus-standalone:19530"
-    graphrag_kg_service_url: str = "http://datamate-kg:8080"
+    graphrag_kg_service_url: str = "http://datamate-backend:8080"
     graphrag_kg_internal_token: str = ""
 
     # GraphRAG - 检索策略默认值

runtime/datamate-python/app/module/kg_graphrag/kb_access.py

@@ -69,7 +69,7 @@ class KnowledgeBaseAccessValidator:
         try:
             client = self._get_client()
             resp = await client.get(
-                f"/knowledge-base/{knowledge_base_id}",
+                f"/api/knowledge-base/{knowledge_base_id}",
                 headers={"X-User-Id": user_id},
             )
             if resp.status_code == 200:

runtime/datamate-python/app/module/kg_graphrag/kg_client.py

@@ -23,7 +23,7 @@ class KGServiceClient:
     def __init__(
         self,
         *,
-        base_url: str = "http://datamate-kg:8080",
+        base_url: str = "http://datamate-backend:8080",
         internal_token: str = "",
         timeout: float = 30.0,
     ) -> None:
@@ -95,7 +95,7 @@ class KGServiceClient:
     ) -> list[EntitySummary]:
         client = self._get_client()
         resp = await client.get(
-            f"/knowledge-graph/{graph_id}/query/search",
+            f"/api/knowledge-graph/{graph_id}/query/search",
             params={"q": query, "size": size},
             headers=self._headers(user_id),
         )
@@ -159,7 +159,7 @@ class KGServiceClient:
     ) -> tuple[list[EntitySummary], list[RelationSummary]]:
         client = self._get_client()
         resp = await client.post(
-            f"/knowledge-graph/{graph_id}/query/subgraph/export",
+            f"/api/knowledge-graph/{graph_id}/query/subgraph/export",
             params={"depth": depth},
             json={"entityIds": entity_ids},
             headers=self._headers(user_id),

runtime/datamate-python/app/module/kg_graphrag/test_kb_access.py

@@ -148,7 +148,7 @@ class TestCheckAccess:
             _run(validator.check_access("kb-123", "user-456"))
 
         call_kwargs = mock_http.get.call_args
-        assert "/knowledge-base/kb-123" in call_kwargs.args[0]
+        assert "/api/knowledge-base/kb-123" in call_kwargs.args[0]
         assert call_kwargs.kwargs["headers"]["X-User-Id"] == "user-456"
 
     def test_cross_user_access_denied(self, validator: KnowledgeBaseAccessValidator):