Fix Chromecast casting with Redirect profile and auto refresh stream on session end

[dennisoderwald]

This PR fixes two issues (#118) with Chromecast functionality:

Issue 1: Redirect profile doesn't properly construct stream URL for Chromecast

Changes:

• Modified loadMedia() in cast.js to detect when a raw stream URL (from Redirect profile) is passed
• Instead of just appending parameters, the function now properly constructs a /stream endpoint URL with:
  • url
  • profileId
  • userAgentId
• Uses guideState.settings.activeStreamProfileId to determine if the current profile is a redirect profile

Issue 2: No stream reload when Chromecast session ends

Changes:

• Added import of forceRefreshStream from player.js in cast.js
• In handleSessionStateChange(), when SESSION_ENDED occurs, the function now calls forceRefreshStream()
• This automatically restarts the stream in the local player, similar to clicking the refresh button

[dennisoderwald]

It would make sense to introduce a function such as buildStreamUrl to avoid redundancy when constructing the stream URL. However, I didn't want to make a design decision here @ardoviniandrea.