feat(notifications): add overlay notifications with position config

- Add Catppuccin Macchiato overlay notification stack with 3s transient timeout
- Add `notifications.overlayPosition` config (top-left | top | top-right)
- Route startup tokenization and subtitle annotation status through configured surfaces
- Deduplicate rapid subtitle mode toggle notifications
- Change `both` to mean overlay + system; add `osd-system` as legacy alias for old behavior
- Keep `osd`/`osd-system` as config-file-only legacy values; Settings UI offers overlay/system/both/none

plugin/subminer/aniskip.lua

@@ -467,7 +467,9 @@ function M.create(ctx)
 		if in_intro and not state.aniskip.prompt_shown and now >= intro_start and now < hint_window_end then
 			local key = opts.aniskip_button_key ~= "" and opts.aniskip_button_key or DEFAULT_ANISKIP_BUTTON_KEY
 			local message = string.format(opts.aniskip_button_text, key)
-			mp.osd_message(message, tonumber(opts.aniskip_button_duration) or 3)
+			if opts.osd_messages then
+				mp.osd_message(message, tonumber(opts.aniskip_button_duration) or 3)
+			end
 			state.aniskip.prompt_shown = true
 		end
 	end

plugin/subminer/messages.lua

@@ -2,6 +2,7 @@ local M = {}
 
 function M.create(ctx)
 	local mp = ctx.mp
+	local opts = ctx.opts
 	local process = ctx.process
 	local aniskip = ctx.aniskip
 	local hover = ctx.hover
@@ -56,7 +57,9 @@ function M.create(ctx)
 			hover.handle_hover_message(payload_json)
 		end)
 		mp.register_script_message("subminer-stats-toggle", function()
-			mp.osd_message("Stats: press ` (backtick) in overlay", 3)
+			if opts.osd_messages then
+				mp.osd_message("Stats: press ` (backtick) in overlay", 3)
+			end
 		end)
 		mp.register_script_message("subminer-reload-session-bindings", function()
 			ctx.session_bindings.reload_bindings()