fix: correct plugin marketplace name for CI validation

plugin-dev is in claude-plugins-official, not claude-code-plugins.
Also adds plugin_marketplaces URL for discovery.

.github/workflows/validate.yml

@@ -45,7 +45,8 @@ jobs:
         with:
           use_bedrock: "true"
           use_sticky_comment: true
-          plugins: "plugin-dev@claude-code-plugins"
+          plugins: "plugin-dev@claude-plugins-official"
+          plugin_marketplaces: "https://github.com/anthropics/claude-plugins-official.git"
           prompt: |
             You are validating the codeflash-agent Claude Code plugin. This plugin has:
             - 6 agents in `agents/` (router + setup + 4 domain agents)
@@ -198,5 +199,6 @@ jobs:
         uses: anthropics/claude-code-action@v1
         with:
           use_bedrock: "true"
-          plugins: "plugin-dev@claude-code-plugins"
+          plugins: "plugin-dev@claude-plugins-official"
+          plugin_marketplaces: "https://github.com/anthropics/claude-plugins-official.git"
           claude_args: '--model us.anthropic.claude-sonnet-4-6 --allowedTools "Agent,Read,Edit,Write,Glob,Grep,Bash(git status*),Bash(git diff*),Bash(git add *),Bash(git commit *),Bash(git push*),Bash(git log*),Bash(gh pr comment*),Bash(gh pr view*),Bash(gh pr diff*)"'