refactor(core): CORE-16 type display modes and own fullscreen lifetimes

test/types/display-pip.ts

@@ -0,0 +1,13 @@
+import type { PipHost } from '../../packages/artplayer/src/display/types'
+import pipMix from '../../packages/artplayer/src/player/pipMix'
+
+declare const host: PipHost
+pipMix(host)
+const state: HTMLElement | null | boolean = host.pip
+// @ts-expect-error Native PiP historically returns the element or null, not just boolean.
+const booleanOnly: boolean = host.pip
+host.pip = true
+host.pip = false
+// @ts-expect-error PiP setters accept a boolean input.
+host.pip = 'picture-in-picture'
+export { booleanOnly, state }