feat(mcp): restrict grep_app tools to librarian agent only (#395)

* feat(mcp): restrict grep_app tools to librarian agent only

Reduces token usage by disabling grep_app MCP tools globally and enabling them only for the librarian agent, which uses them for GitHub code search during documentation lookups.

Changes:
- Add grep_app_* tool disable globally in config.tools
- Add grep_app_* tool enable for librarian agent
- Remove grep_app references from explore agent prompt (no access)

Closes #394

* chore: changes by sisyphus-dev-ai

---------

Co-authored-by: sisyphus-dev-ai <sisyphus-dev-ai@users.noreply.github.com>

assets/oh-my-opencode.schema.json

@@ -64,7 +64,8 @@
           "ralph-loop",
           "preemptive-compaction",
           "compaction-context-injector",
-          "claude-code-hooks"
+          "claude-code-hooks",
+          "auto-slash-command"
         ]
       }
     },