Dune Analytics MCP Server

# Tasks: Add MCP Resources with dune:// URI Scheme ## 1. Latest Result Resource - [x] 1.1 Implement resource handler for dune://query/{query_id}/latest - [x] 1.2 Call client.get_latest_result() (no credits consumed) - [x] 1.3 Return JSON formatted result rows - [x] 1.4 Set MIME type to application/json ## 2. Query SQL Resource - [x] 2.1 Implement resource handler for dune://query/{query_id}/sql - [x] 2.2 Fetch query metadata and extract query_sql field - [x] 2.3 Return raw SQL text - [x] 2.4 Set MIME type to text/plain ## 3. Execution Status Resource - [x] 3.1 Implement resource handler for dune://execution/{execution_id}/status - [x] 3.2 Return JSON object with state field - [x] 3.3 Set MIME type to application/json ## 4. Error Handling - [x] 4.1 Handle query/execution not found - [x] 4.2 Handle no cached result available - [x] 4.3 Return appropriate error messages ## 5. Validation - [x] 5.1 Test latest resource returns cached data - [x] 5.2 Verify no credits consumed for latest resource - [x] 5.3 Test SQL resource returns query text - [x] 5.4 Test status resource returns valid states