Add web UI for WebDAV files and CardDAV contacts

Files browser (web/files):
- Alphabetical listing grouped folders-then-files
- Upload via button or drag-and-drop, including whole folders
- Folder creation
- Fixed layout for long filenames without spaces (table-fixed + break-all)

Contacts (web/contacts):
- Full CRUD for CardDAV contacts (create/edit/delete)
- VCF import (multi-card files) and export (single/all)
- Photo upload with preview, birthday field
- TYPE labels (private/business) for phone, email, address
- Repeatable multi-input rows for phones/emails/addresses instead of textareas
- Sanitizes a known malformed TYPE parameter pattern from some vCard
  exporters (e.g. Nextcloud Contacts) that otherwise caused phone numbers
  to be silently dropped on import

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

internal/web/server.go

@@ -45,6 +45,15 @@ func (s *Server) Handler(staticFS http.FileSystem) http.Handler {
 	mux.HandleFunc("/resources/calendar", s.requireLogin(s.handleCalendarResource))
 	mux.HandleFunc("/resources/calendar/color", s.requireLogin(s.handleCalendarColor))
 	mux.HandleFunc("/resources/addressbook", s.requireLogin(s.handleAddressBookResource))
+	mux.HandleFunc("/files/{path...}", s.requireLogin(s.handleFiles))
+	mux.HandleFunc("/contacts", s.requireLogin(s.handleContactsHome))
+	mux.HandleFunc("/contacts/{book}", s.requireLogin(s.handleContactsList))
+	mux.HandleFunc("/contacts/{book}/new", s.requireLogin(s.handleContactNew))
+	mux.HandleFunc("/contacts/{book}/import", s.requireLogin(s.handleContactImport))
+	mux.HandleFunc("/contacts/{book}/export", s.requireLogin(s.handleContactExportAll))
+	mux.HandleFunc("/contacts/{book}/{id}/edit", s.requireLogin(s.handleContactEdit))
+	mux.HandleFunc("/contacts/{book}/{id}/delete", s.requireLogin(s.handleContactDelete))
+	mux.HandleFunc("/contacts/{book}/{id}/export", s.requireLogin(s.handleContactExportOne))
 
 	return mux
 }