fix(views): auto-split whitespace in custom args entries

Users naturally type `--model claude-sonnet-4-20250514` on one line,
but the backend needs them as separate tokens. Now `entriesToArgs`
splits each entry by whitespace before saving, so the API receives
`["--model", "claude-sonnet-4-20250514"]` instead of a single string.

Also updated placeholder and description to show the natural input
format.

server/pkg/agent/claude.go

@@ -37,7 +37,6 @@ func (b *claudeBackend) Execute(ctx context.Context, prompt string, opts ExecOpt
 	args := buildClaudeArgs(opts, b.cfg.Logger)
 
 	cmd := exec.CommandContext(runCtx, execPath, args...)
-	b.cfg.Logger.Debug("agent command", "exec", execPath, "args", args)
 	cmd.WaitDelay = 10 * time.Second
 	if opts.Cwd != "" {
 		cmd.Dir = opts.Cwd

server/pkg/agent/codex.go

@@ -42,7 +42,6 @@ func (b *codexBackend) Execute(ctx context.Context, prompt string, opts ExecOpti
 
 	codexArgs := append([]string{"app-server", "--listen", "stdio://"}, filterCustomArgs(opts.CustomArgs, codexBlockedArgs, b.cfg.Logger)...)
 	cmd := exec.CommandContext(runCtx, execPath, codexArgs...)
-	b.cfg.Logger.Debug("agent command", "exec", execPath, "args", codexArgs)
 	if opts.Cwd != "" {
 		cmd.Dir = opts.Cwd
 	}

server/pkg/agent/gemini.go

@@ -35,7 +35,6 @@ func (b *geminiBackend) Execute(ctx context.Context, prompt string, opts ExecOpt
 	args := buildGeminiArgs(prompt, opts, b.cfg.Logger)
 
 	cmd := exec.CommandContext(runCtx, execPath, args...)
-	b.cfg.Logger.Debug("agent command", "exec", execPath, "args", args)
 	cmd.WaitDelay = 10 * time.Second
 	if opts.Cwd != "" {
 		cmd.Dir = opts.Cwd

server/pkg/agent/hermes.go

@@ -36,7 +36,6 @@ func (b *hermesBackend) Execute(ctx context.Context, prompt string, opts ExecOpt
 
 	hermesArgs := append([]string{"acp"}, opts.CustomArgs...)
 	cmd := exec.CommandContext(runCtx, execPath, hermesArgs...)
-	b.cfg.Logger.Debug("agent command", "exec", execPath, "args", hermesArgs)
 	if opts.Cwd != "" {
 		cmd.Dir = opts.Cwd
 	}

server/pkg/agent/openclaw.go

@@ -60,7 +60,6 @@ func (b *openclawBackend) Execute(ctx context.Context, prompt string, opts ExecO
 	args = append(args, "--message", prompt)
 
 	cmd := exec.CommandContext(runCtx, execPath, args...)
-	b.cfg.Logger.Debug("agent command", "exec", execPath, "args", args)
 	cmd.WaitDelay = 10 * time.Second
 	if opts.Cwd != "" {
 		cmd.Dir = opts.Cwd

server/pkg/agent/opencode.go

@@ -55,7 +55,6 @@ func (b *opencodeBackend) Execute(ctx context.Context, prompt string, opts ExecO
 	args = append(args, prompt)
 
 	cmd := exec.CommandContext(runCtx, execPath, args...)
-	b.cfg.Logger.Debug("agent command", "exec", execPath, "args", args)
 	cmd.WaitDelay = 10 * time.Second
 	if opts.Cwd != "" {
 		cmd.Dir = opts.Cwd