fix: expand marketplace to list individual skills for proper discovery

[christso]

Problem

The marketplace.json configuration lists all skills under a single plugin entry pointing to the ./skills directory. Claude Code's plugin system cannot discover individual skills nested in subdirectories without explicit entries for each one.

As a result, users adding the marketplace see no available skills to install.

Solution

This PR expands marketplace.json to list all 10 context engineering skills as individual plugin entries, each with:

• Correct source path (e.g., ./skills/context-fundamentals)
• Description from its SKILL.md file
• Relevant keywords for discoverability

Also updates README.md with corrected installation instructions.

Skills Now Available

1. context-fundamentals - Understand context components and constraints
2. context-optimization - Apply optimization techniques to extend context capacity
3. context-compression - Design compression strategies for long-running sessions
4. context-degradation - Recognize and mitigate context degradation patterns
5. multi-agent-patterns - Design multi-agent architectures
6. memory-systems - Implement memory architectures for agents
7. evaluation - Build evaluation frameworks
8. advanced-evaluation - Master LLM-as-a-Judge techniques
9. project-development - Design and build LLM-powered projects
10. tool-design - Design tools for effective agent use
11. book-sft-pipeline - Train models to write in any author's style

Testing

Users can now properly discover and install skills:

/plugin marketplace add muratcankoylan/Agent-Skills-for-Context-Engineering
/plugin install context-fundamentals@context-engineering-marketplace

Related

Closes #18

[muratcankoylan]

Thanks for flagging this @christso . You identified that the marketplace discovery was broken due to the single-entry configuration.

I've implemented a comprehensive fix in fix/marketplace-discovery (commit 67f2bea) that resolves this by:

1. Explicitly defining all 10+ skills in marketplace.json as individual plugins.
2. Adding the required .claude-plugin/plugin.json manifest to every skill directory (which is necessary for the discovery mechanism to work reliably beyond just the marketplace entry).
3. Updating the installation documentation.

The fix is now merged into main. I'm closing the PR in favor of that implementation, but I appreciate you catching this early!