Improve portable launch, forge persistence, and operator auth UX.

Persist build extra_files for Build Manager history, print dashboard login on every start, add libp2p for Mesh P2P forge, defer WebSocket until login, and split devrun.bat from LAUNCH.bat with USB deck auto-detection.

server/internal/api/agent_config_test.go

@@ -0,0 +1,39 @@
+package api
+
+import "testing"
+
+func TestAgentConfigPoolHostOrDefault(t *testing.T) {
+	t.Run("empty uses fallback", func(t *testing.T) {
+		cfg := AgentForgeConfig{}
+		if got := cfg.poolHostOrDefault("fallback.host"); got != "fallback.host" {
+			t.Fatalf("got %q, want fallback.host", got)
+		}
+	})
+	t.Run("explicit host wins", func(t *testing.T) {
+		cfg := AgentForgeConfig{PoolHost: "pool.example.com"}
+		if got := cfg.poolHostOrDefault("fallback"); got != "pool.example.com" {
+			t.Fatalf("got %q, want pool.example.com", got)
+		}
+	})
+}
+
+func TestAgentConfigPoolPortOrDefault(t *testing.T) {
+	t.Run("zero uses fallback", func(t *testing.T) {
+		cfg := AgentForgeConfig{}
+		if got := cfg.poolPortOrDefault(3333); got != 3333 {
+			t.Fatalf("got %d, want 3333", got)
+		}
+	})
+	t.Run("negative uses fallback", func(t *testing.T) {
+		cfg := AgentForgeConfig{PoolPort: -1}
+		if got := cfg.poolPortOrDefault(3333); got != 3333 {
+			t.Fatalf("got %d, want 3333", got)
+		}
+	})
+	t.Run("explicit port wins", func(t *testing.T) {
+		cfg := AgentForgeConfig{PoolPort: 443}
+		if got := cfg.poolPortOrDefault(3333); got != 443 {
+			t.Fatalf("got %d, want 443", got)
+		}
+	})
+}