feat(01-01): boot hello app and dispatch greeter:hello

- Add party plugin registry with Register-before-Boot activation
- Add backpack, compass, bonfire, and pact capability interfaces
- Add examples/hello with two compiled plugin modules

compass/config.go

@@ -0,0 +1,72 @@
+package compass
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/knadh/koanf/parsers/yaml"
+	"github.com/knadh/koanf/v2"
+)
+
+// Config is a YAML configuration tree with dot-path access.
+type Config struct {
+	k *koanf.Koanf
+}
+
+// Load reads config/<section>.yaml files from dir. Each filename stem becomes
+// the top-level section, so config/app.yaml key name is app.name.
+func Load(dir string) (*Config, error) {
+	k := koanf.New(".")
+	entries, err := os.ReadDir(dir)
+	if err != nil {
+		return nil, fmt.Errorf("compass: read config dir %s: %w", dir, err)
+	}
+	parser := yaml.Parser()
+	for _, entry := range entries {
+		if entry.IsDir() {
+			continue
+		}
+		name := entry.Name()
+		section, ok := sectionName(name)
+		if !ok {
+			continue
+		}
+		path := filepath.Join(dir, name)
+		raw, err := os.ReadFile(path)
+		if err != nil {
+			return nil, fmt.Errorf("compass: read %s: %w", path, err)
+		}
+		parsed, err := parser.Unmarshal(raw)
+		if err != nil {
+			return nil, fmt.Errorf("compass: parse %s: %w", path, err)
+		}
+		if parsed == nil {
+			parsed = map[string]any{}
+		}
+		if err := k.Set(section, parsed); err != nil {
+			return nil, fmt.Errorf("compass: set section %s: %w", section, err)
+		}
+	}
+	return &Config{k: k}, nil
+}
+
+// String returns the string value at path, or "" if unset.
+func (c *Config) String(path string) string {
+	if c == nil || c.k == nil {
+		return ""
+	}
+	return c.k.String(path)
+}
+
+func sectionName(filename string) (string, bool) {
+	switch {
+	case strings.HasSuffix(filename, ".yaml"):
+		return strings.TrimSuffix(filename, ".yaml"), true
+	case strings.HasSuffix(filename, ".yml"):
+		return strings.TrimSuffix(filename, ".yml"), true
+	default:
+		return "", false
+	}
+}

compass/config_test.go

@@ -0,0 +1,23 @@
+package compass
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestLoadStringFromAppSection(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "app.yaml")
+	if err := os.WriteFile(path, []byte("name: hello-app\n"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	cfg, err := Load(dir)
+	if err != nil {
+		t.Fatalf("Load: %v", err)
+	}
+	if got := cfg.String("app.name"); got != "hello-app" {
+		t.Fatalf("String(app.name) = %q, want hello-app", got)
+	}
+}