feat: 配置变量系统与 target id/name 双字段标识

- 新增顶层 variables 段支持 string/number/boolean 字面量
- target 字符串字段支持 、、{...} 转义语法
- 变量解析优先级: variables -> process.env -> 默认值 -> 报错
- 完整引用保留原始类型，部分引用拼接为字符串
- 变量替换在 YAML 解析后、AJV 校验前执行
- 替换仅作用于 targets，跳过 id/type 字段
- target 新增必填 id 字段作为唯一标识，name 改为可选展示名称
- 数据库存储/API/前端全面迁移到 id 标识
- 统一 checker 运行时类型检查为 es-toolkit predicates
- 同步 delta specs 到主 specs，归档 config-variables 变更

probes.example.yaml

@@ -1,3 +1,5 @@
+# yaml-language-server: $schema=./probe-config.schema.json
+
 server:
   host: "127.0.0.1"
   port: 3000
@@ -14,10 +16,17 @@ defaults:
   cmd:
     maxOutputBytes: "1MB"
 
+variables:
+  env_name: "演示"
+  httpbin_base: "https://httpbin.org"
+  api_token: "Bearer demo-token"
+  sqlite_url: "sqlite://:memory:"
+
 targets:
   # ========== HTTP targets ==========
 
-  - name: "Baidu 首页可用"
+  - id: "baidu-home"
+    name: "Baidu 首页可用"
     type: http
     group: "搜索引擎"
     http:
@@ -26,15 +35,17 @@ targets:
       status: [200]
       maxDurationMs: 5000
 
-  - name: "JSON API — 完整流水线"
+  - id: "httpbin-json"
+    name: "${env_name} JSON API — 完整流水线"
     type: http
     group: "后端服务"
     interval: "1m"
     timeout: "15s"
     http:
-      url: "https://httpbin.org/json"
+      url: "${httpbin_base}/json"
       headers:
         Accept: "application/json"
+        Authorization: "${api_token|Bearer fallback-token}"
     expect:
       headers:
         Content-Type:
@@ -49,10 +60,11 @@ targets:
             contains: "Wake"
         - regex: '"title"'
 
-  - name: "POST 接口测试"
+  - id: "httpbin-post"
+    name: "POST 接口测试"
     type: http
     http:
-      url: "https://httpbin.org/post"
+      url: "${httpbin_base}/post"
       method: POST
       headers:
         Content-Type: "application/json"
@@ -69,7 +81,8 @@ targets:
 
   # ========== Cmd targets ==========
 
-  - name: "Bun 版本输出匹配"
+  - id: "bun-version"
+    name: "Bun 版本输出匹配"
     type: cmd
     group: "系统检查"
     cmd:
@@ -80,7 +93,8 @@ targets:
       stdout:
         - match: "^\\d+\\.\\d+\\.\\d+"
 
-  - name: "多规则 stdout 顺序校验"
+  - id: "bun-stdout-rules"
+    name: "多规则 stdout 顺序校验"
     type: cmd
     interval: "5m"
     cmd:
@@ -92,7 +106,8 @@ targets:
         - match: "\\d+\\.\\d+\\.\\d+"
         - contains: "healthy"
 
-  - name: "stderr 内容检查"
+  - id: "bun-stderr"
+    name: "stderr 内容检查"
     type: cmd
     cmd:
       exec: "bun"
@@ -104,18 +119,20 @@ targets:
 
   # ========== DB targets ==========
 
-  - name: "SQLite 内存数据库连接测试"
+  - id: "sqlite-connect"
+    name: "SQLite 内存数据库连接测试"
     type: db
     group: "数据库"
     db:
-      url: "sqlite://:memory:"
+      url: "${sqlite_url}"
     expect:
       maxDurationMs: 1000
 
-  - name: "SQLite 内存数据库多列结果校验"
+  - id: "sqlite-query"
+    name: "SQLite 内存数据库多列结果校验"
     type: db
     db:
-      url: "sqlite://:memory:"
+      url: "${sqlite_url}"
       query: "SELECT 1 as id, 'Alice' as name, 'engineer' as role"
     expect:
       rowCount: