fix: dashboard funnel crash, comrade user, Cloudflare tunnel auto-start

Add runtime comrade account, null-safe spread funnel API/UI, server-started
cloudflared connector with Calibrate token field and builtin fallback, and
simplify LAUNCH to delegate tunnel startup to AetherForge.

server/internal/cloudflared/launcher_stub.go

@@ -0,0 +1,9 @@
+//go:build !windows
+
+package cloudflared
+
+// Start is a no-op on non-Windows builds.
+func Start(_, _, _ string) error { return nil }
+
+// Stop is a no-op on non-Windows builds.
+func Stop() {}