feat(builtin-skills): add playwright skill with MCP config and disabled_skills option

- Add playwright as builtin skill with MCP server configuration
- Add disabled_skills config option to disable specific builtin skills
- Update BuiltinSkill type to include mcpConfig field
- Update skill merger to handle mcpConfig from builtin to loaded skills
- Merge disabled_skills config and filter unavailable builtin skills at plugin init
- Update README with Built-in Skills documentation
- Regenerate JSON schema

🤖 Generated with assistance of OhMyOpenCode (https://github.com/code-yeongyu/oh-my-opencode)

src/features/opencode-skill-loader/merger.ts

@@ -21,7 +21,7 @@ const SCOPE_PRIORITY: Record<SkillScope, number> = {
 function builtinToLoaded(builtin: BuiltinSkill): LoadedSkill {
   const definition: CommandDefinition = {
     name: builtin.name,
-    description: `(builtin - Skill) ${builtin.description}`,
+    description: `(opencode - Skill) ${builtin.description}`,
     template: builtin.template,
     model: builtin.model,
     agent: builtin.agent,
@@ -37,6 +37,7 @@ function builtinToLoaded(builtin: BuiltinSkill): LoadedSkill {
     compatibility: builtin.compatibility,
     metadata: builtin.metadata as Record<string, string> | undefined,
     allowedTools: builtin.allowedTools,
+    mcpConfig: builtin.mcpConfig,
   }
 }