frontend: fix wallet push silently skipping in form dialogs

The "send to wallet" step in the appointment/invoice/prescription/
patient-edit/scribe dialogs was gated on sync.linked, which resolves
asynchronously via getWalletLink in an effect. A fast save (or a
transient failure that collapsed it to false) left a wallet-linked
patient looking unlinked, so the dialog took the else branch and pushed
nothing.

- Add ensureLinked() to useWalletSync: awaits getWalletLink at submit and
  returns the resolved status. Each of the 5 dialogs now awaits it before
  deciding whether to show the wallet step.
- Harden push() to drop empty/whitespace changes (the backend 400s on an
  empty change set) and add a translated summaryFallback so the step
  never sends an empty summary.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/lib/i18n/locales/ar/translation.json

@@ -2257,6 +2257,7 @@
       "prescription": "وصفة جديدة: {{drug}}",
       "demographics": "تم تحديث البيانات الديموغرافية",
       "note": "ملاحظة سريرية جديدة"
-    }
+    },
+    "summaryFallback": "تم تحديث السجل"
   }
 }

frontend/lib/i18n/locales/de/translation.json

@@ -2237,6 +2237,7 @@
       "prescription": "Neues Rezept: {{drug}}",
       "demographics": "Stammdaten aktualisiert",
       "note": "Neue klinische Notiz"
-    }
+    },
+    "summaryFallback": "Datensatz aktualisiert"
   }
 }

frontend/lib/i18n/locales/en/translation.json

@@ -2237,6 +2237,7 @@
       "prescription": "New prescription: {{drug}}",
       "demographics": "Demographics updated",
       "note": "New clinical note"
-    }
+    },
+    "summaryFallback": "Record updated"
   }
 }

frontend/lib/i18n/locales/fr/translation.json

@@ -2237,6 +2237,7 @@
       "prescription": "Nouvelle ordonnance : {{drug}}",
       "demographics": "Données démographiques mises à jour",
       "note": "Nouvelle note clinique"
-    }
+    },
+    "summaryFallback": "Dossier mis à jour"
   }
 }

frontend/lib/i18n/locales/so/translation.json

@@ -2237,6 +2237,7 @@
       "prescription": "Rijeeto cusub: {{drug}}",
       "demographics": "Xogta bukaanka la cusboonaysiiyay",
       "note": "Qoraal caafimaad cusub"
-    }
+    },
+    "summaryFallback": "Diiwaanka waa la cusboonaysiiyay"
   }
 }