Replace broken QR login with manual JSESSIONID cookie

Samsung rebuilt account.samsung.com as a JS SPA backed by /iam/oauth2,
so the integration's HTML-scraping QR flow can no longer find the
signin URL and /accounts/v1/FMM2/signInWithQrCode now 404s. The STF
backend (chkLogin.do, getDeviceList.do, ...) is unchanged.

Replace the multi-step QR config flow with a single form that asks
the user to paste the JSESSIONID cookie copied from a logged-in
browser session at smartthingsfind.samsung.com. validate_jsessionid
hits chkLogin.do to verify the cookie before accepting it.

Also bundle in earlier compatibility fixes for newer HA: store
devices in hass.data so the coordinator can look them up by
entry_id, and use async_on_update on the device_tracker entity.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

custom_components/smartthings_find/translations/en.json

@@ -3,9 +3,18 @@
     "abort": {
       "reauth_successful": "Reauthentication successful."
     },
-    "progress": {
-      "task_stage_one": "Preparing, please wait...",
-      "task_stage_two": "To login please scan the following QR Code with your Galaxy device. You can also login using this browser by clicking [here]({url}). \n\n![QR Code](data:image/png;base64,{qr_code})\n\nUnable to scan the code? Go to [signin.samsung.com/key](https://signin.samsung.com/key/) and enter the following code:\n\n## ```{code}```\n"
+    "error": {
+      "invalid_auth": "Cookie was rejected by SmartThings Find. Make sure you copied the JSESSIONID value (not the whole cookie header) from a tab where you are logged in.",
+      "empty_cookie": "Please paste a JSESSIONID value."
+    },
+    "step": {
+      "user": {
+        "title": "Paste JSESSIONID cookie",
+        "description": "Samsung's QR code login flow no longer works (account.samsung.com was rebuilt). Until it is replaced you have to obtain the session cookie manually:\n\n1. Open [smartthingsfind.samsung.com](https://smartthingsfind.samsung.com/) in a regular browser and log in.\n2. Open DevTools → Application (Chrome) or Storage (Firefox) → Cookies → smartthingsfind.samsung.com.\n3. Copy the value of the **JSESSIONID** cookie and paste it below.\n\nThe cookie usually stays valid for several weeks. When it expires Home Assistant will trigger a reauth and you repeat these steps.",
+        "data": {
+          "jsessionid": "JSESSIONID"
+        }
+      }
     }
   },
   "options": {
@@ -19,4 +28,4 @@
       }
     }
   }
-}
+}