fix(a11y): distinguish errors from empty states and close naming gaps

Add isError branches with a retry affordance to the mood, illness, and
vorsorge lists so a failed read no longer renders as "no entries yet"
and invites duplicate re-entry, matching the labs and cycle pattern.

Make the admin backups table reachable on a phone with a card fallback,
name the admin language and timezone selects and the AI raw-data switch
for screen readers, and replace the touch-unreachable title= help on the
glucose clinical panels with a tap-capable info popover.

Route the password-strength label through the AA-tuned semantic tokens,
underline the register login link so it is not distinguished by colour
alone, give the labs load error alert semantics, and explain why the
target editor Save button is disabled with aria-invalid and a live
alert.

src/components/targets/target-edit-sheet.tsx

@@ -307,6 +307,52 @@ function TargetEditSheetBody({
 
   const canSave = !isDerivedMetric && primaryValid && secondaryValid && !busy;
 
+  // Per-field validity so the inputs can carry `aria-invalid` and the
+  // disabled Save button gets a spoken explanation instead of greying out
+  // silently. The order check (min < max) flags both ends of the pair.
+  const primaryOrderInvalid =
+    Number.isFinite(minNum) && Number.isFinite(maxNum) && minNum >= maxNum;
+  const primaryMinInvalid =
+    primaryBounds != null &&
+    (!Number.isFinite(minNum) ||
+      minNum < primaryBounds.min ||
+      minNum > primaryBounds.max ||
+      primaryOrderInvalid);
+  const primaryMaxInvalid =
+    primaryBounds != null &&
+    (!Number.isFinite(maxNum) ||
+      maxNum < primaryBounds.min ||
+      maxNum > primaryBounds.max ||
+      primaryOrderInvalid);
+
+  const secondaryOrderInvalid =
+    isBp &&
+    Number.isFinite(diaMinNum) &&
+    Number.isFinite(diaMaxNum) &&
+    diaMinNum >= diaMaxNum;
+  const secondaryMinInvalid =
+    isBp &&
+    secondaryBounds != null &&
+    (!Number.isFinite(diaMinNum) ||
+      diaMinNum < secondaryBounds.min ||
+      diaMinNum > secondaryBounds.max ||
+      secondaryOrderInvalid);
+  const secondaryMaxInvalid =
+    isBp &&
+    secondaryBounds != null &&
+    (!Number.isFinite(diaMaxNum) ||
+      diaMaxNum < secondaryBounds.min ||
+      diaMaxNum > secondaryBounds.max ||
+      secondaryOrderInvalid);
+
+  let validationMessage: string | null = null;
+  if (!isDerivedMetric && primaryBounds && (!primaryValid || !secondaryValid)) {
+    validationMessage =
+      primaryOrderInvalid || secondaryOrderInvalid
+        ? t("targets.edit.validationOrder")
+        : t("targets.edit.validationBounds");
+  }
+
   const handleSave = () => {
     if (!canSave) return;
     if (isBp) {
@@ -426,6 +472,7 @@ function TargetEditSheetBody({
                   value={displayMin}
                   onChange={(e) => setMinStr(e.target.value)}
                   disabled={busy}
+                  aria-invalid={primaryMinInvalid}
                   data-slot="target-edit-min-input"
                 />
               </div>
@@ -444,6 +491,7 @@ function TargetEditSheetBody({
                   value={displayMax}
                   onChange={(e) => setMaxStr(e.target.value)}
                   disabled={busy}
+                  aria-invalid={primaryMaxInvalid}
                   data-slot="target-edit-max-input"
                 />
               </div>
@@ -467,6 +515,7 @@ function TargetEditSheetBody({
                     value={displayDiaMin}
                     onChange={(e) => setDiaMinStr(e.target.value)}
                     disabled={busy}
+                    aria-invalid={secondaryMinInvalid}
                     data-slot="target-edit-dia-min-input"
                   />
                 </div>
@@ -483,6 +532,7 @@ function TargetEditSheetBody({
                     value={displayDiaMax}
                     onChange={(e) => setDiaMaxStr(e.target.value)}
                     disabled={busy}
+                    aria-invalid={secondaryMaxInvalid}
                     data-slot="target-edit-dia-max-input"
                   />
                 </div>
@@ -496,6 +546,16 @@ function TargetEditSheetBody({
                 unit: primaryBounds.unit,
               })}
             </p>
+
+            {validationMessage && (
+              <p
+                role="alert"
+                data-slot="target-edit-validation"
+                className="text-destructive text-xs"
+              >
+                {validationMessage}
+              </p>
+            )}
           </div>
         )}
       </form>