The Feishu bot now calls the app_slash_commands OpenAPI at startup to register its common commands (menu, new, help, status, compact, sessionlist, workspacelist, watch, unwatch, watchlist, archived) as native Slash Commands, so typing / in a Feishu direct-message input box pops the command panel and tapping a command triggers it.
The command list is owned and pushed by dsh-im; it does not depend on the dsh/Harness backend. Registration is best-effort and runs asynchronously, so it never blocks the long-connection startup or message delivery when the app lacks the application:app_slash_command:read/write scopes.
Adds src/channels/feishu/slash-command-registry.mjs (manifest, list/create/delete, idempotent sync), wires it into feishu-runtime.mjs (slashCommands config flag + status fields), and covers it with tests.
