feat: polish toolbar, live online count via SSE + emulator 3-state

- Add emulator status 3-state (unknown/green/red) with tooltip
- Extract shared primary button style/constants for DRY toolbar code
- Add emulatorUnknown translations to all 25 locales
- Bump Next.js to 16.3.4
- Fix RCON delivery timeout caching (15s TTL / shared across clients)
- Who's-online tooltip throttled to max 1 request per 30s

src/app/client/client-view.tsx

@@ -400,17 +400,28 @@ export function ClientView({
 								boxShadow: "inset 0 1px 0 rgba(255,255,255,0.20)",
 							}}
 							role="status"
+							aria-label={
+								emulatorOk === null
+									? tToolbar("emulatorUnknown")
+									: emulatorOk
+										? tToolbar("emulatorOnline")
+										: tToolbar("emulatorOffline")
+							}
 							title={
-								emulatorOk === false
-									? tToolbar("emulatorOffline")
-									: tToolbar("emulatorOnline")
+								emulatorOk === null
+									? tToolbar("emulatorUnknown")
+									: emulatorOk
+										? tToolbar("emulatorOnline")
+										: tToolbar("emulatorOffline")
 							}
 						>
 							<span className="relative flex h-2.5 w-2.5">
-								{emulatorOk === false ? (
-									<span className="relative inline-flex rounded-full h-2.5 w-2.5 bg-destructive ring-2 ring-destructive/30 shadow-[0_0_8px_rgba(239,68,68,0.8)]" />
-								) : (
+								{emulatorOk === null ? (
+									<span className="relative inline-flex rounded-full h-2.5 w-2.5 bg-muted-foreground ring-2 ring-muted-foreground/30" />
+								) : emulatorOk ? (
 									<span className="relative inline-flex rounded-full h-2.5 w-2.5 bg-success ring-2 ring-success/30 shadow-[0_0_8px_rgba(52,211,153,0.8)]" />
+								) : (
+									<span className="relative inline-flex rounded-full h-2.5 w-2.5 bg-destructive ring-2 ring-destructive/30 shadow-[0_0_8px_rgba(239,68,68,0.8)]" />
 								)}
 							</span>
 						</div>