fix(opds): epubcfi Atom compatibility, path deduplication, auth tokens

- Add <title> and <author><name> elements to Atom feed for compatibility
- Remove doubled /opds/opds/ path prefix in feed URLs
- Include ?token= auth param on all OPDS URLs
- Serve kepub links only for Kobo devices
- Fix URL construction for entries and acquisitions

internal/opds/feed.go

@@ -22,8 +22,8 @@ type Feed struct {
 
 type Entry struct {
 	ID         string      `xml:"id"`
-	Title      string      `xml:"dc:title"`
-	Creator    string      `xml:"dc:creator,omitempty"`
+	Title      string      `xml:"title"`
+	Author     *Author     `xml:"author,omitempty"`
 	Updated    string      `xml:"updated"`
 	Summary    string      `xml:"summary,omitempty"`
 	Links      []Link      `xml:"link"`
@@ -32,6 +32,12 @@ type Entry struct {
 	Categories []Category  `xml:"category,omitempty"`
 }
 
+type Author struct {
+	XMLName xml.Name `xml:"author"`
+	Name    string   `xml:"name"`
+	URI     string   `xml:"uri,omitempty"`
+}
+
 type Link struct {
 	Href string `xml:"href,attr"`
 	Type string `xml:"type,attr"`
@@ -85,14 +91,17 @@ func (f *Feed) AddEntry(entry Entry) {
 
 // NewEntry creates a new OPDS entry
 func NewEntry(id, title, creator, updated string) Entry {
-	return Entry{
+	e := Entry{
 		ID:       id,
 		Title:    title,
-		Creator:  creator,
 		Updated:  updated,
 		Links:    []Link{},
 		Metadata: []Meta{},
 	}
+	if creator != "" {
+		e.Author = &Author{Name: creator}
+	}
+	return e
 }
 
 // AddAcquisitionLink adds an acquisition link to the entry