fix addon sources selection

[silentbil]

• dont auto start movie if its disable via settings
• The selector was showing "No sources found" immediately, then sources would appear 3–4 seconds later (when a slow addon like Stremiogram responded)
• Added completedAddons/totalAddons tracking in DetailsUiState, updated progressively as each addon responds
• Shows "Searching addons (X/Y)..." spinner while addons are still fetching and no sources have appeared yet
• Once any sources appear, the list shows immediately — loading state never blocks visible results
• Fixed a race condition where the modal opened with isLoadingStreams = false for one frame (state reset is now synchronous before the coroutine launches)