Add Kavita 0.9.x+ compatibility fixes

[MohamedMaged9258]

API changes:

• Handle 404 NotFound (in addition to 204 NoContent) for getVolume and getChapter
  endpoints, which now return 404 instead of 204 when a resource is not found
• Include libraryId in api/series/scan request body to match the new RefreshSeriesDto
  contract that requires both seriesId and libraryId
• Handle 404 NotFound (in addition to 204 NoContent) for getVolume and getChapter
  endpoints, which now return 404 instead of 204 when a resource is not found
• Include libraryId in api/series/scan request body to match the new RefreshSeriesDto
  contract that requires both seriesId and libraryId
• Replace removed api/upload/reset-chapter-lock endpoint with api/upload/chapter
  using an empty URL and lockCover=false to reset chapter cover locks

Browser extension:

• Fix Kavita detection in AppState to match the new title format "Page (Kavita)"
  in addition to the standalone "Kavita" title used on the home page
• Fix navbar button not remounting after reader mode; the Angular @if directive
  removes and re-adds the element itself, which getElementsByTagName cannot
  match against the element it is called on
• Skip remount when the button is already present to prevent duplicate insertions
• Replace fragile children[4] index with ul.navbar-nav querySelector for a stable
  insertion point regardless of sidenav toggle visibility