feat(frontend): Redis browser pane stub #1895

Parent

#1850

Goal

Basic key list + value view wired to Redis commands.

Done when

• Stub usable against local Redis

How to work

• Branch: issue/<n>-slug from epic/tauri-migration (create epic branch if missing).
• One PR → Closes #<n>.
• Target PR base: epic/tauri-migration until the SQLite slice is green.
• Do not edit Flutter app code unless this issue says so.