fix: bug fixes, test coverage, and CI workflow

- Fix Nodes.First() panic on empty slice (return nil)
- Fix ticker leak in archive.go (create once, defer Stop)
- Fix cookie path matching for empty and root paths
- Fix lost query params in google.go (u.Query().Set was discarded)
- Fix type assertion panic in useragents.go
- Fix dropped date parse error in powerball.go
- Remove unreachable dead code in megamillions.go and powerball.go
- Simplify document.go WaitForNetworkIdle, remove unused root field
- Remove debug fmt.Println calls across codebase
- Replace panic(err) with stderr+exit in all cmd/ programs
- Fix duckduckgo cmd: remove useless defer, return error on bad safesearch
- Fix archive cmd: ToConfig returns error instead of panicking
- Add 39+ unit tests across 6 new test files
- Add Gitea Actions CI workflow (build, test, vet in parallel)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

sites/google/google_test.go

@@ -0,0 +1,39 @@
+package google
+
+import (
+	"testing"
+)
+
+func TestConfig_Validate_Defaults(t *testing.T) {
+	c := Config{}
+	c = c.validate()
+
+	if c.BaseURL != "google.com" {
+		t.Errorf("BaseURL = %q, want %q", c.BaseURL, "google.com")
+	}
+	if c.Language != "en" {
+		t.Errorf("Language = %q, want %q", c.Language, "en")
+	}
+	if c.Country != "us" {
+		t.Errorf("Country = %q, want %q", c.Country, "us")
+	}
+}
+
+func TestConfig_Validate_Preserves(t *testing.T) {
+	c := Config{
+		BaseURL:  "google.co.uk",
+		Language: "fr",
+		Country:  "uk",
+	}
+	c = c.validate()
+
+	if c.BaseURL != "google.co.uk" {
+		t.Errorf("BaseURL = %q, want %q", c.BaseURL, "google.co.uk")
+	}
+	if c.Language != "fr" {
+		t.Errorf("Language = %q, want %q", c.Language, "fr")
+	}
+	if c.Country != "uk" {
+		t.Errorf("Country = %q, want %q", c.Country, "uk")
+	}
+}