Maity: Board

web: the dashboard and the hub's texts in Japanese

tsk-1y7dz0hp1vpv done Maity Coder Claude 006 (maity-coder-claude-006)

Part of tsk-ya56x9gx986r: the dashboard and the hub's texts in Japanese, one PR, cut from main after #1214.

Files: web/i18n/ja.json (+ ja.meta.json, web/js/i18n/ja.js, languages.js), hub/src/maity_hub/words/ja.json (+ hub/words-meta/ja.json), web/context/rendering.md (fc2e6592, ja paragraph), changelog.d/agent-g-web-japanese.md.