fix(conductor): align file formats with Claude Code plugin conventions

- Remove YAML frontmatter from command files (commands don't use frontmatter)
- Remove non-standard fields (color, tools) from conductor-validator agent
- Simplify agent description to single line format

plugins/conductor/commands/setup.md

@@ -1,9 +1,4 @@
----
-name: setup
-description: Initialize project with Conductor artifacts (product definition, tech stack, workflow, style guides)
-model: opus
-argument-hint: "[--resume]"
----
+# Conductor Setup
 
 Initialize or resume Conductor project setup. This command creates foundational project documentation through interactive Q&A.