i18n: convert feature pages, dialogs, auth sub-pages and nav to t()

Move all hardcoded UI strings in the appointments, prescriptions, tasks,
messages, activity, analysis and patients views (plus their dialogs and
detail sheets), the remaining auth pages (verify-email, forgot/reset
password, accept-invite, onboarding), the clinic form and the sidebar user
menu into i18next keys in en/translation.json. Clinical option values
(appointment types, frequencies) stay canonical. English-only; no new
locale yet.

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

frontend/components/tasks/task-detail-sheet.tsx

@@ -1,5 +1,7 @@
 "use client";
 
+import { useTranslation } from "react-i18next";
+
 import { Badge } from "@/components/ui/badge";
 import { Button } from "@/components/ui/button";
 import {
@@ -19,15 +21,9 @@ const priorityVariant: Record<Priority, "destructive" | "secondary" | "outline">
     low: "outline",
   };
 
-const priorityLabel: Record<Priority, string> = {
-  high: "High",
-  medium: "Medium",
-  low: "Low",
-};
-
 // Right-side Sheet showing a single task's full detail, opened from the Tasks
 // list (mirrors the Patients table → PatientDetailSheet pattern). The task is
-// passed in directly since tasks live in local state — no async fetch.
+// passed in directly from the page.
 export function TaskDetailSheet({
   task,
   open,
@@ -39,6 +35,7 @@ export function TaskDetailSheet({
   onOpenChange: (open: boolean) => void;
   onToggle: (id: string) => void;
 }) {
+  const { t } = useTranslation();
   return (
     <Sheet onOpenChange={onOpenChange} open={open}>
       <SheetPopup className="sm:max-w-xl" side="right">
@@ -46,7 +43,7 @@ export function TaskDetailSheet({
           <SheetTitle
             className={cn(task?.done && "text-muted-foreground line-through")}
           >
-            {task?.title ?? "Task"}
+            {task?.title ?? t("tasks.detail.fallbackTitle")}
           </SheetTitle>
         </SheetHeader>
         <SheetPanel className="min-h-0 flex-1">
@@ -54,22 +51,34 @@ export function TaskDetailSheet({
             <div className="flex flex-col gap-5">
               <div>
                 <Badge variant={priorityVariant[task.priority]}>
-                  {priorityLabel[task.priority]} priority
+                  {t("tasks.detail.priorityBadge", {
+                    priority: t(`tasks.priority.${task.priority}`),
+                  })}
                 </Badge>
               </div>
 
               <dl className="grid grid-cols-[6rem_1fr] gap-x-3 gap-y-2 text-sm">
-                <dt className="text-muted-foreground">Status</dt>
+                <dt className="text-muted-foreground">
+                  {t("tasks.detail.status")}
+                </dt>
                 <dd className="text-foreground">
-                  {task.done ? "Completed" : "Open"}
+                  {task.done
+                    ? t("tasks.detail.completed")
+                    : t("tasks.detail.open")}
                 </dd>
-                <dt className="text-muted-foreground">Assignee</dt>
+                <dt className="text-muted-foreground">
+                  {t("tasks.detail.assignee")}
+                </dt>
                 <dd className="text-foreground">{task.assignee}</dd>
-                <dt className="text-muted-foreground">Due</dt>
+                <dt className="text-muted-foreground">
+                  {t("tasks.detail.due")}
+                </dt>
                 <dd className="text-foreground">{task.due}</dd>
                 {task.patient && (
                   <>
-                    <dt className="text-muted-foreground">Patient</dt>
+                    <dt className="text-muted-foreground">
+                      {t("tasks.detail.patient")}
+                    </dt>
                     <dd className="text-foreground">{task.patient}</dd>
                   </>
                 )}
@@ -77,7 +86,9 @@ export function TaskDetailSheet({
 
               {task.notes && (
                 <div className="flex flex-col gap-1.5">
-                  <span className="text-muted-foreground text-xs">Details</span>
+                  <span className="text-muted-foreground text-xs">
+                    {t("tasks.detail.details")}
+                  </span>
                   <p className="whitespace-pre-wrap text-foreground text-sm leading-relaxed">
                     {task.notes}
                   </p>
@@ -90,7 +101,9 @@ export function TaskDetailSheet({
                   type="button"
                   variant={task.done ? "outline" : "default"}
                 >
-                  {task.done ? "Reopen task" : "Mark complete"}
+                  {task.done
+                    ? t("tasks.detail.reopen")
+                    : t("tasks.detail.complete")}
                 </Button>
               </div>
             </div>