dsh-prompt-suggestions: Add history rollback and next sentence prediction to the DSH input box

The plugin "dsh-prompt-suggestions" (package name: dsh-composer-suggestions) adds historical rollback and next-sentence prediction to the DSH input box. The Up/Down keys allow scrolling through all questions sent in the current session (including pasted content, accepted predictions, and queued messages). Ctrl+Up opens the history panel for searching, while the Right key accepts gray "ghost" text as an editable draft. Rollbacks do not trigger an automatic send and are constrained by the condition `source.kind = user`. The recommended installation command is `dsh plugin --profile desktop add github:Heeweelee/dsh-prompt-suggestions`, with alternatives available via npm, tarball, or local directory. The plugin features a Host/Client split architecture and includes logic for smart retries, preventing filler text, and local fallbacks.