chore: add description to themed puzzle selection

docs/best_1000_puzzles_by_theme.md

@@ -1,3 +1,12 @@
+# 🏆 Best 1000 Puzzles by Theme 🧩
+
+Below you find the best (= highest popularity score, ordered by number of plays) 1000 puzzles for each of the [available themes](https://lichess.org/training/themes) 🎯, sourced from the [lichess puzzles database](https://database.lichess.org/#puzzles) 📊.
+
+The CSV files contain two columns - the PGN of the puzzle, and the corresponding tags 🏷️ - and are compatible with the [Anki-Chess-2.0](https://github.com/TowelSniffer/Anki-Chess-2.0) template 🗂️.
+
+If you want to generate your own puzzles, filtered by popularity, rating, number of plays and puzzle themes, you can do so within the "Puzzle Database" tab of `chessli2` ♟️.
+
+
 | Name                    | Description                                                                                                         | Link                                                                                                      |
 |-------------------------|---------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------|
 | Advanced pawn           | One of your pawns is deep into the opponent position, maybe threatening to promote.                                 | [Link](https://github.com/pwenker/chessli2/blob/main/puzzles/advancedPawn.csv)                                      |

src/chessli2/app.py

@@ -16,8 +16,7 @@ puzzle_themes_file = Path("docs/puzzle_themes.md")
 with gr.Blocks(title="Chessli2") as chessli2_gradio_app:
     with gr.Tab("Welcome"):
         readme = readme_file.read_text()
-        gr_readme = readme.split("---")[2].strip()
-        gr.Markdown(gr_readme)
+        gr.Markdown(readme)
 
     with gr.Tab("Games & Mistakes"):
         gr.Markdown(
@@ -26,7 +25,7 @@ with gr.Blocks(title="Chessli2") as chessli2_gradio_app:
             
             Here you can fetch your games and mistakes from your **game history** 🎮. You can filter by time control, type of mistakes, and date range.
             
-            When you are happy, you can download a CSV file with the selected mistakes' PGNs to practice them with Anki 📥."""
+            When you are happy, you can download a CSV file with the selected mistakes' PGNs to practice them with Anki 📥.""",
         )
 
         user_name = gr.Textbox(