Support metadata in list_problems tool

Updated list_problems tool to handle both old (string list) and new
(dict list with metadata) formats from LLMBenchSimple.

Changes:
- ListProblemsTool now checks if problems are Dicts or Strings
- For Dict format, merges problem metadata with default fields
- Maintains backward compatibility with string-only problem lists
- Ensures all problems have id, name, description, category fields

This enables LLMBenchSimple modules to provide rich metadata like
enable_anthropic_api, custom descriptions, etc. through list_problems.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: Keno

src/tools/list_problems.jl

@@ -31,15 +31,31 @@ function ClaudeMCPTools.execute(tool::ListProblemsTool, params::Dict)
         try
             problems = Base.invokelatest(tool.list_fn)
 
-            # Format as JSON with problem list
-            problems_json = Dict(
-                "problems" => [Dict(
-                    "id" => p,
-                    "name" => p,
+            # Handle two formats:
+            # 1. Vector of Dicts (new format with metadata)
+            # 2. Vector of Strings (old format, backward compatible)
+            problems_list = if !isempty(problems) && problems[1] isa Dict
+                # New format: problems already have metadata
+                # Ensure each has at least an id, name, description, category
+                [merge(
+                    Dict{String,Any}(
+                        "name" => get(p, "id", ""),
+                        "description" => "",
+                        "category" => "general"
+                    ),
+                    p  # Metadata from @bench overrides defaults
+                ) for p in problems]
+            else
+                # Old format: convert strings to dicts
+                [Dict{String,Any}(
+                    "id" => string(p),
+                    "name" => string(p),
                     "description" => "",
                     "category" => "general"
                 ) for p in problems]
-            )
+            end
+
+            problems_json = Dict("problems" => problems_list)
 
             return Dict(
                 "content" => [Dict(