test(protocols,skills): add 90 tests for MCP types + skill loader/runner

zclaw-protocols: +43 tests covering mcp_types serde, ContentBlock
variants, transport config builders, and domain type roundtrips.

zclaw-skills: +47 tests covering SKILL.md/TOML parsing, auto-classify,
PromptOnlySkill execution, and SkillManifest/SkillResult roundtrips.

Batch 8 of audit plan (plans/stateless-petting-rossum.md).

crates/zclaw-protocols/tests/mcp_transport_tests.rs

@@ -0,0 +1,55 @@
+//! Tests for MCP Transport configuration (McpServerConfig)
+//!
+//! These tests cover McpServerConfig builder methods without spawning processes.
+
+use std::collections::HashMap;
+use zclaw_protocols::McpServerConfig;
+
+#[test]
+fn npx_config_creates_correct_command() {
+    let config = McpServerConfig::npx("@modelcontextprotocol/server-memory");
+    assert_eq!(config.command, "npx");
+    assert_eq!(config.args, vec!["-y", "@modelcontextprotocol/server-memory"]);
+    assert!(config.env.is_empty());
+    assert!(config.cwd.is_none());
+}
+
+#[test]
+fn node_config_creates_correct_command() {
+    let config = McpServerConfig::node("/path/to/server.js");
+    assert_eq!(config.command, "node");
+    assert_eq!(config.args, vec!["/path/to/server.js"]);
+}
+
+#[test]
+fn python_config_creates_correct_command() {
+    let config = McpServerConfig::python("mcp_server.py");
+    assert_eq!(config.command, "python");
+    assert_eq!(config.args, vec!["mcp_server.py"]);
+}
+
+#[test]
+fn env_adds_variables() {
+    let config = McpServerConfig::node("server.js")
+        .env("API_KEY", "secret123")
+        .env("DEBUG", "true");
+    assert_eq!(config.env.get("API_KEY").unwrap(), "secret123");
+    assert_eq!(config.env.get("DEBUG").unwrap(), "true");
+}
+
+#[test]
+fn cwd_sets_working_directory() {
+    let config = McpServerConfig::node("server.js").cwd("/tmp/work");
+    assert_eq!(config.cwd.unwrap(), "/tmp/work");
+}
+
+#[test]
+fn combined_builder_pattern() {
+    let config = McpServerConfig::npx("@scope/server")
+        .env("PORT", "3000")
+        .cwd("/app");
+    assert_eq!(config.command, "npx");
+    assert_eq!(config.args.len(), 2);
+    assert_eq!(config.env.len(), 1);
+    assert_eq!(config.cwd.unwrap(), "/app");
+}