feat: Archivum skeleton — Go/GraphQL backend + Vue 3 PWA frontend

Full project scaffold: multi-stage Dockerfile (ARM64/AMD64), AsciiDoc↔TipTap
bridge, Setup Wizard, CodeMirror source editor, Git-backed storage layer,
LDAP+JWT auth skeleton, Tailwind mobile-first layout, and VS Code build/push
tasks targeting registry at 192.168.0.19:5000.

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

backend/internal/storage/storage.go

@@ -0,0 +1,70 @@
+package storage
+
+import (
+	"errors"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+// Store manages AsciiDoc files on disk.
+type Store struct {
+	root string
+}
+
+func New(root string) (*Store, error) {
+	if err := os.MkdirAll(root, 0755); err != nil {
+		return nil, err
+	}
+	return &Store{root: root}, nil
+}
+
+// Read returns the content of a document by its slug path (e.g. "guides/install").
+func (s *Store) Read(slug string) (string, error) {
+	data, err := os.ReadFile(s.filePath(slug))
+	if err != nil {
+		if errors.Is(err, os.ErrNotExist) {
+			return "", ErrNotFound
+		}
+		return "", err
+	}
+	return string(data), nil
+}
+
+// Write persists content to disk, creating parent directories as needed.
+func (s *Store) Write(slug, content string) error {
+	path := s.filePath(slug)
+	if err := os.MkdirAll(filepath.Dir(path), 0755); err != nil {
+		return err
+	}
+	return os.WriteFile(path, []byte(content), 0644)
+}
+
+// Delete removes a document from disk.
+func (s *Store) Delete(slug string) error {
+	return os.Remove(s.filePath(slug))
+}
+
+// List returns all document slugs under an optional prefix.
+func (s *Store) List(prefix string) ([]string, error) {
+	base := filepath.Join(s.root, filepath.FromSlash(prefix))
+	var slugs []string
+	err := filepath.WalkDir(base, func(path string, d os.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+		if !d.IsDir() && strings.HasSuffix(path, ".adoc") {
+			rel, _ := filepath.Rel(s.root, path)
+			slug := strings.TrimSuffix(filepath.ToSlash(rel), ".adoc")
+			slugs = append(slugs, slug)
+		}
+		return nil
+	})
+	return slugs, err
+}
+
+func (s *Store) filePath(slug string) string {
+	return filepath.Join(s.root, filepath.FromSlash(slug)+".adoc")
+}
+
+var ErrNotFound = errors.New("document not found")