Add Japanese localization entries for forms and abilities from the latest games

[nikollson]

Change description

Add Japanese localization entries for Pokemon forms and abilities from the latest games.

This PR includes:

• Japanese ja / ja-hrkt form names for selected Mega and Gigantamax forms
  • Gigantamax Form / キョダイマックスのすがた
  • Mega Clefable / メガピクシー
• Japanese ability names for newer abilities
  • Supersweet Syrup / かんろなミツ
  • Mega Sol / メガソーラー
• Japanese ability flavor text entries for abilities that already have Japanese names
  • When the Pokémon takes damage from a move, it burns the attacker. / 技のダメージを受けると　相手をやけど状態にする。

The Japanese entries in this PR were checked against in-game text from Pokemon Scarlet/Violet and Pokemon Champions, as well as official Pokedex pages, for example:

• https://zukan.pokemon.co.jp/?sort_type=5

How to test:

• Run make build-db
• Run make test
• Start the local server with make serve
• Verify affected endpoints such as:
  • /api/v2/pokemon-form/<form>/
  • /api/v2/ability/<ability>/

AI coding assistance disclosure

I used AI coding assistance to help create small helper scripts for inspecting the repository data, listing Japanese localization entries that were not yet covered for newer game content.

I manually reviewed and edited the final data changes myself, then verified the results locally with:

• make build-db
• make test
• direct checks against affected API endpoints

Contributor check list

• I have written a description of the contribution and explained its motivation.
• I have written tests for my code changes (if applicable).
• I have read and understood the AI Assisted Contribution guidelines.
• I will own this change in production, and I am prepared to fix any bugs caused by my code change.