h2fe1/dsh-deepseek-account-balance: Add a balance label to the bottom bar of the DSH input field

The plugin `h2fe1/dsh-deepseek-account-balance` places a balance label next to the context usage on the right side of the DSH input box, displaying the balance of the currently logged-in DeepSeek account. It directly utilizes the read-only methods `account.getState` and `account.getBalance` from the client-side `deepseek-account` service. Requests are sent to the Platform carrying credentials from the Host. The page cannot access the token, no new routes are added, no inference requests are initiated, and the account quota is not modified. It can be installed by entering the repository address in the plugin installation entry of the DSH Web GUI, or by using `dsh plugin --profile <profile> add github:h2fe1/dsh-deepseek-account-balance`. Display rules include three states: logged in, logged out, and query failed. It refreshes on click, and automatically refreshes every 60 seconds when the page is visible. The amount is formatted according to the platform's two-decimal rule, and the language follows the interface language. The plugin has no configuration items and does not read keys. It requires Node ^22.19.0 || >=24.0.0 and DSH >=0.2.0-rc.2. The license is MIT.