Add full test suite with unit, integration, and E2E smoke tests.

Introduce test.bat orchestrating Go/Vitest/Playwright phases, expand coverage across server, agent, and dashboard, and document in tests/README.md.

server/internal/pool/proxy_test.go

@@ -0,0 +1,34 @@
+package pool
+
+import (
+	"testing"
+)
+
+func TestAuthenticateSetsLoginRequestID(t *testing.T) {
+	p := &Proxy{
+		config: &Config{Wallet: "48test", Password: "x"},
+		stopCh: make(chan struct{}),
+	}
+	// authenticate will fail without real conn, but should bump loginRequestID before write fails
+	_ = p.authenticate()
+	if p.loginRequestID != 1 {
+		t.Fatalf("expected loginRequestID=1, got %d", p.loginRequestID)
+	}
+	_ = p.authenticate()
+	if p.loginRequestID != 2 {
+		t.Fatalf("expected loginRequestID=2 after second login, got %d", p.loginRequestID)
+	}
+}
+
+func TestHandleResponseLoginByTrackedID(t *testing.T) {
+	p := &Proxy{
+		config:         &Config{Wallet: "48test"},
+		stopCh:         make(chan struct{}),
+		loginRequestID: 42,
+	}
+	// Should not panic; login branch taken when ID matches
+	p.handleResponse(StratumResponse{
+		ID:     42,
+		Result: []byte(`{"id":"pool-session","status":"OK"}`),
+	})
+}