feat(coding-agent): support provider arguments for login

packages/coding-agent/src/core/slash-commands.ts

@@ -13,11 +13,12 @@ export interface SlashCommandInfo {
 export interface BuiltinSlashCommand {
 	name: string;
 	description: string;
+	argumentHint?: string;
 }
 
 export const BUILTIN_SLASH_COMMANDS: ReadonlyArray<BuiltinSlashCommand> = [
 	{ name: "settings", description: "Open settings menu" },
-	{ name: "model", description: "Select model (opens selector UI)" },
+	{ name: "model", description: "Select model (opens selector UI)", argumentHint: "<provider/model>" },
 	{ name: "scoped-models", description: "Enable/disable models for Ctrl+P cycling" },
 	{ name: "export", description: "Export session (HTML default, or specify path: .html/.jsonl)" },
 	{ name: "import", description: "Import and resume a session from a JSONL file" },
@@ -31,7 +32,7 @@ export const BUILTIN_SLASH_COMMANDS: ReadonlyArray<BuiltinSlashCommand> = [
 	{ name: "clone", description: "Duplicate the current session at the current position" },
 	{ name: "tree", description: "Navigate session tree (switch branches)" },
 	{ name: "trust", description: "Save project trust decision for future sessions" },
-	{ name: "login", description: "Configure provider authentication" },
+	{ name: "login", description: "Configure provider authentication", argumentHint: "<provider>" },
 	{ name: "logout", description: "Remove provider authentication" },
 	{ name: "new", description: "Start a new session" },
 	{ name: "compact", description: "Manually compact the session context" },