feat(adapter): define Adapter interface and FileSet

internal/adapter/adapter.go

@@ -0,0 +1,39 @@
+// Package adapter defines the harness adapter interface and FileSet.
+package adapter
+
+import "github.com/lukaszraczylo/harness-sync/internal/canonical"
+
+type Kind int
+
+const (
+	RenderedFile Kind = iota
+	SymlinkFile
+	SymlinkDir
+)
+
+func (k Kind) String() string {
+	switch k {
+	case RenderedFile:
+		return "rendered"
+	case SymlinkFile:
+		return "symlink-file"
+	case SymlinkDir:
+		return "symlink-dir"
+	}
+	return "unknown"
+}
+
+type Adapter interface {
+	Name() string
+	Detect() bool
+	Render(b *canonical.Bundle) (*FileSet, error)
+	Import(home string) (*ImportResult, error)
+}
+
+type ImportResult struct {
+	Instructions string
+	Skills       []canonical.Skill
+	Agents       []canonical.Agent
+	MCP          []canonical.MCPServer
+	Profiles     []canonical.Profile
+}