Set yearly as default config and note full dataset sorting

README.md

@@ -18,6 +18,7 @@ size_categories:
 configs:
 - config_name: yearly
   data_files: "yearly/data.csv"
+  default: true
 - config_name: full
   data_files: "full/data.csv"
 ---
@@ -58,7 +59,7 @@ ds = load_dataset('ronantakizawa/github-top-developers', 'yearly')
 - `popular_repos` (string): Top repositories (comma-separated)
 
 ### Configuration: `full`
-Complete daily trending data with 41,841 entries
+Complete daily trending data with 41,841 entries (sorted by date: most recent first)
 
 ```python
 from datasets import load_dataset
@@ -69,7 +70,7 @@ ds = load_dataset('ronantakizawa/github-top-developers', 'full')
 - `name` (string): Developer/organization GitHub username
 - `rank` (int): Position in trending (1-25)
 - `popular_repo` (string): Associated repository at the time
-- `date` (string): Snapshot date (YYYY-MM-DD)
+- `date` (string): Snapshot date (YYYY-MM-DD, sorted descending)
 
 ## 🏆 Scoring Methodology