refactor(claude-code-plugin-loader): split loader.ts into per-type loaders

Extract plugin component loading into dedicated modules:
- discovery.ts: plugin directory detection
- plugin-path-resolver.ts: path resolution logic
- agent-loader.ts, command-loader.ts, hook-loader.ts
- mcp-server-loader.ts, skill-loader.ts

src/features/claude-code-plugin-loader/mcp-server-loader.ts

@@ -0,0 +1,48 @@
+import { existsSync } from "fs"
+import type { McpServerConfig } from "../claude-code-mcp-loader/types"
+import { expandEnvVarsInObject } from "../claude-code-mcp-loader/env-expander"
+import { transformMcpServer } from "../claude-code-mcp-loader/transformer"
+import type { ClaudeCodeMcpConfig } from "../claude-code-mcp-loader/types"
+import { log } from "../../shared/logger"
+import type { LoadedPlugin } from "./types"
+import { resolvePluginPaths } from "./plugin-path-resolver"
+
+export async function loadPluginMcpServers(
+  plugins: LoadedPlugin[],
+): Promise<Record<string, McpServerConfig>> {
+  const servers: Record<string, McpServerConfig> = {}
+
+  for (const plugin of plugins) {
+    if (!plugin.mcpPath || !existsSync(plugin.mcpPath)) continue
+
+    try {
+      const content = await Bun.file(plugin.mcpPath).text()
+      let config = JSON.parse(content) as ClaudeCodeMcpConfig
+
+      config = resolvePluginPaths(config, plugin.installPath)
+      config = expandEnvVarsInObject(config)
+
+      if (!config.mcpServers) continue
+
+      for (const [name, serverConfig] of Object.entries(config.mcpServers)) {
+        if (serverConfig.disabled) {
+          log(`Skipping disabled MCP server "${name}" from plugin ${plugin.name}`)
+          continue
+        }
+
+        try {
+          const transformed = transformMcpServer(name, serverConfig)
+          const namespacedName = `${plugin.name}:${name}`
+          servers[namespacedName] = transformed
+          log(`Loaded plugin MCP server: ${namespacedName}`, { path: plugin.mcpPath })
+        } catch (error) {
+          log(`Failed to transform plugin MCP server "${name}"`, error)
+        }
+      }
+    } catch (error) {
+      log(`Failed to load plugin MCP config: ${plugin.mcpPath}`, error)
+    }
+  }
+
+  return servers
+}