cleanup: `handleListDevices` builds output with string concatenation loop instead of `strings.Join`

[gitcoder89431]

Problem

In internal/mcpserver/server.go, handleListDevices builds its output with an intermediate []string slice and then a second loop concatenating strings:

var lines []string
for _, d := range devices {
    lines = append(lines, fmt.Sprintf("[%s] %s — %s", d.Status, d.Name, d.ID))
}
out := ""
for _, l := range lines {
    out += l + "\n"
}

This is two passes, an extra allocation, and less idiomatic Go.

Fix

Use strings.Builder or collapse into a single loop:

var b strings.Builder
for _, d := range devices {
    fmt.Fprintf(&b, "[%s] %s — %s\n", d.Status, d.Name, d.ID)
}
return mcp.NewToolResultText(b.String()), nil

[gitcoder89431]

Fixed in f9cf96a