Add PokeDB sprite downloading (100x100 WebP)

Download pokemon sprites from PokeDB CDN during import, cached locally
as {pokeapi_id}.webp. Replaces PokeAPI GitHub sprite URLs. ~4.6MB for
all 1119 unique sprites.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tools/import-pokedb/import_pokedb/mappings.py

@@ -464,6 +464,19 @@ class PokemonMapper:
 
         return None
 
+    def get_sprite_url(self, pokemon_form_identifier: str | None) -> str | None:
+        """Get the PokeDB CDN sprite URL (100x100 medium) for a form identifier."""
+        if not pokemon_form_identifier:
+            return None
+        form_record = self._pokedb_form_index.get(pokemon_form_identifier, {})
+        return form_record.get("main_image_normal_path_medium")
+
+    def get_form_data(self, pokemon_form_identifier: str | None) -> dict | None:
+        """Get the full PokeDB form record for a form identifier."""
+        if not pokemon_form_identifier:
+            return None
+        return self._pokedb_form_index.get(pokemon_form_identifier)
+
     def report_unmapped(self) -> None:
         """Print warnings for any unmapped identifiers."""
         if self._unmapped: