Initialize blog scaffold

Add the CLI, site, and sample content so the project can run locally.

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

backend/internal/cli/slug_test.go

@@ -0,0 +1,38 @@
+package cli
+
+import "testing"
+
+func TestSanitizeSlug(t *testing.T) {
+	tests := map[string]string{
+		"Hello Astro":        "hello-astro",
+		" Go / Astro_Blog! ": "go-astro-blog",
+		"Already--Clean":     "already-clean",
+		"喜欢你":                "",
+		"abc123":             "abc123",
+	}
+
+	for input, want := range tests {
+		if got := sanitizeSlug(input); got != want {
+			t.Fatalf("sanitizeSlug(%q) = %q, want %q", input, got, want)
+		}
+	}
+}
+
+func TestFallbackSlug(t *testing.T) {
+	if got := fallbackSlug("Hello Astro"); got != "hello-astro" {
+		t.Fatalf("fallbackSlug english = %q", got)
+	}
+
+	got := fallbackSlug("喜欢你")
+	if len(got) <= len("post-") || got[:5] != "post-" {
+		t.Fatalf("fallbackSlug non-ascii = %q, want post-*", got)
+	}
+}
+
+func TestFormatYAMLStringList(t *testing.T) {
+	got := formatYAMLStringList([]string{"go", `astro "site"`})
+	want := `["go", "astro \"site\""]`
+	if got != want {
+		t.Fatalf("formatYAMLStringList = %q, want %q", got, want)
+	}
+}