feat: bind/unbind by id, video streaming proxy, unmute default, library refresh, hamburger click-outside

- Core API: bind/unbind accept id (integer PK) when face_id is null
- Tauri proxy: stream video responses instead of buffering for seek bar
- VideoPlayer: remove muted attribute, unmute by default
- LibraryView: call invalidateFiles() before ensureFiles() on register/unregister
- PeopleView: close sort panel on click-outside, not just hamburger toggle
- bind_face: prefer face_id, fallback to id when face_id is null

src/directives/vObserve.ts

@@ -0,0 +1,44 @@
+import { Directive } from 'vue'
+
+const vObserve: Directive<HTMLElement> = {
+  mounted(el, binding) {
+    if (typeof binding.value !== 'function') return
+
+    const callback = binding.value
+
+    const observer = new IntersectionObserver(
+      (entries) => {
+        if (!entries.length) return
+        if (entries[0].isIntersecting) {
+          callback()
+          observer.disconnect()
+        }
+      },
+      { rootMargin: '200px 0px' }
+    )
+
+    observer.observe(el)
+    ;(el as any)._io = observer
+
+    requestAnimationFrame(() => {
+      const rect = el.getBoundingClientRect()
+      if (
+        rect.top < window.innerHeight + 200 &&
+        rect.bottom > -200 &&
+        rect.width > 0
+      ) {
+        callback()
+        observer.disconnect()
+        ;(el as any)._io = undefined
+      }
+    })
+  },
+  unmounted(el) {
+    if ((el as any)._io) {
+      ;(el as any)._io.disconnect()
+      ;(el as any)._io = undefined
+    }
+  },
+}
+
+export default vObserve