frontend: deep-link via ?instance=; client/frontend default to :9090; Makefile help; v1.1.0

- cmd/frontend/web: honour ?instance=<hostname> query parameter on the
  initial scope hydration so /view/?instance=lb-ams opens the dashboard
  scoped to that maglevd. The cookie is updated on consumption; an
  unknown name still falls back to the first server via App.tsx.

- cmd/client, cmd/frontend: --server now accepts bare hostnames. A new
  internal/netutil.EnsurePort canonicalises addresses by appending
  :9090 when no port is given, with bracketing for bare IPv6 literals.
  Unit test covers the IPv4/IPv6/bracketed/already-ported permutations.

- Makefile: new self-documenting `help` target as the default rule;
  every user-facing target now carries a `## ` description that the
  awk-based help auto-extracts. fixstyle-web skips with a friendly
  message when prettier isn't installed instead of failing on npx.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

cmd/frontend/main.go

@@ -16,8 +16,14 @@ import (
 	"time"
 
 	buildinfo "git.ipng.ch/ipng/vpp-maglev/cmd"
+	"git.ipng.ch/ipng/vpp-maglev/internal/netutil"
 )
 
+// defaultGRPCPort is the maglevd gRPC port. Lets operators write
+// "--server chbtl2" or MAGLEV_FRONTEND_SERVERS=chbtl2,chbtl3 without
+// the redundant ":9090" suffix on every entry.
+const defaultGRPCPort = "9090"
+
 func main() {
 	if err := run(); err != nil {
 		slog.Error("startup-fatal", "err", err)
@@ -133,7 +139,7 @@ func parseServers(s string) []string {
 	var out []string
 	for _, part := range strings.Split(s, ",") {
 		if p := strings.TrimSpace(part); p != "" {
-			out = append(out, p)
+			out = append(out, netutil.EnsurePort(p, defaultGRPCPort))
 		}
 	}
 	return out