fix(jellyfin): subtitle timing, resume progress, and overlay sync

- Add per-stream subtitle delay persistence and auto timeline-offset correction
- Strip server-selected subtitle stream from mpv load URL; suppress plugin subtitle rearm and auto-start during app-managed preload
- Fix resume position lost when mpv resets on stop; use last known position for final progress/stopped reports
- Keep Play vs Resume distinct to avoid early seek race on normal play
- Fix discovery resume when remote play sends StartPositionTicks=0 despite saved progress
- Deduplicate show/hide overlay commands using recorded visibility state
- Rewrite docs-site Jellyfin page around cast-to-device UX

plugin/subminer/messages.lua

@@ -6,6 +6,7 @@ function M.create(ctx)
 	local aniskip = ctx.aniskip
 	local hover = ctx.hover
 	local ui = ctx.ui
+	local state = ctx.state
 
 	local function register_script_messages()
 		mp.register_script_message("subminer-start", function(...)
@@ -23,6 +24,10 @@ function M.create(ctx)
 		mp.register_script_message("subminer-visible-overlay-shown", function()
 			process.record_visible_overlay_visibility(true)
 		end)
+		mp.register_script_message("subminer-managed-subtitles-loading", function()
+			state.skip_managed_subtitle_rearm_once = true
+			state.app_managed_playback_pending = true
+		end)
 		mp.register_script_message("subminer-menu", function()
 			ui.show_menu()
 		end)