ShareLinks: add expiry date/time picker and French localization

Replace the 30-days quick button with a native datetime-local picker
(bounded by the server max) so links can expire on an exact date; the
picked date is converted to whole hours through the existing path.

Localize the creation popup and its toasts to French when the Jellyfin
UI language is French, detected from the html lang attribute like the
sibling plugin does; English is the fallback.

manifest.json

@@ -10,11 +10,11 @@
         "versions": [
             {
                 "version": "1.0.0.0",
-                "changelog": "Initial release: ShareLink button on the item menu, temporary guest users confined by tag policy, expiring one-use links, admin dashboard with revoke, and a configurable guest lockdown that hides tag/genre/studio/cast links, the add-to-playlist and add-to-collection actions, and other plugins' UI.",
+                "changelog": "ShareLink button on the item menu, temporary guest users confined by tag policy, expiring links with a date/time picker, admin dashboard with revoke, and a configurable guest lockdown that hides tag/genre/studio/cast links, the add-to-playlist and add-to-collection actions, and other plugins' UI. The creation popup is localized in English and French.",
                 "targetAbi": "10.11.0.0",
                 "sourceUrl": "https://github.com/Franciskid/jellyfin-plugin-sharelinks/releases/download/v1.0.0.0/sharelinks_1.0.0.0.zip",
-                "checksum": "d779dc06a710788d7db698f66d5690bc",
-                "timestamp": "2026-07-07T20:12:00Z"
+                "checksum": "cf29acab1bb5c77ae5a5b8f96891c8a3",
+                "timestamp": "2026-07-07T21:30:00Z"
             }
         ]
     }