fix(ui): disambiguate dashboard quick-add menu items

Phase-3 e2e suite documented an i18n collision: the dashboard's
quick-entry dropdown trigger says "Add" and both menu items underneath
also rendered the bare verb "Add" because `measurements.addMeasurement`
and `mood.addEntry` both translate to "Add". Screen-reader users heard
two indistinguishable rows; the e2e spec was forced to use
`getByRole("menuitem").first()` as a workaround.

The dropdown trigger already says "Add" — the menu items label what's
being added.

  - Add `dashboard.quickAddMeasurement` ("Measurement" / "Messung")
  - Add `dashboard.quickAddMood` ("Mood entry" / "Stimmungseintrag")
  - Wire the two `<DropdownMenuItem>`s on `/`
  - Mark the leading icons `aria-hidden` so the accessible name is
    just the noun
  - Update `e2e/measurement-flow.spec.ts` to target the menu item by
    name (`/measurement|messung/i`) instead of `.first()`

Dialog titles still use the existing `addMeasurement` / `addEntry`
keys — those work in the larger dialog context where "Add" reads fine.

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

src/app/page.tsx

@@ -373,15 +373,19 @@ export default function DashboardPage() {
             </Button>
           </DropdownMenuTrigger>
           <DropdownMenuContent align="end">
+            {/* v1.5 phase-5: the menu items used to share the literal label
+                "Add" with the dialog titles, so screen-reader users heard
+                two indistinguishable "Add" rows in the same dropdown. The
+                trigger already says "Add" — these label what's being added. */}
             <DropdownMenuItem
               onClick={() => setQuickEntryDialog("measurement")}
             >
-              <Activity className="mr-2 h-4 w-4" />
-              {t("measurements.addMeasurement")}
+              <Activity className="mr-2 h-4 w-4" aria-hidden="true" />
+              {t("dashboard.quickAddMeasurement")}
             </DropdownMenuItem>
             <DropdownMenuItem onClick={() => setQuickEntryDialog("mood")}>
-              <Waves className="mr-2 h-4 w-4" />
-              {t("mood.addEntry")}
+              <Waves className="mr-2 h-4 w-4" aria-hidden="true" />
+              {t("dashboard.quickAddMood")}
             </DropdownMenuItem>
           </DropdownMenuContent>
         </DropdownMenu>