merge: sync upstream duckietm/Dev (b2318b9) into feat/react19-modernization

Absorbs 10 upstream commits (JSON5 config support, user-settings reset
password/email/username, wear-badge popup fix, login screen fix, About
update, offer selection logic, client path fix).

Conflicts resolved by keeping the modernized React 19 / Zustand / Form
Actions structure and porting upstream intent surgically:

- bootstrap.ts: kept GetConfiguration().init() pre-init + useEffectEvent,
  added JSON5 import (already wired into the parse fallback)
- LoginView.tsx: kept Form Actions (useActionState/useFormStatus); the
  upstream persistAccessTokenFromPayload(payload) fix was already
  integrated in the modernized SSO branch
- App.tsx: kept useEffectEvent import + StrictMode/ErrorBoundary umbrella
- vite.config.mjs: kept sirv plugin + react-compiler babel; absorbed
  upstream's base: process.env.VITE_BASE || './'
- package.json: kept superset (sirv, Vitest, Zustand, react-colorful,
  React Compiler) + added json5
- User-settings views: accepted upstream (duplicate of local cherry-pick
  2053c8e); notification badge bubble: accepted upstream fix

Verification: yarn typecheck clean, 193/193 Vitest, yarn build green.

src/bootstrap.ts

@@ -1,4 +1,5 @@
 import { GetConfiguration } from '@nitrots/nitro-renderer';
+import JSON5 from 'json5';
 import { configFileUrl, getClientMode, installSecureFetch } from './secure-assets';
 
 const ensureMobileViewport = () =>
@@ -76,7 +77,16 @@ const loadClientMode = async () =>
 
         if(!response.ok) throw new Error(`HTTP ${ response.status }`);
 
-        (window as any).__nitroClientMode = await response.json();
+        const text = await response.text();
+
+        try
+        {
+            (window as any).__nitroClientMode = JSON.parse(text);
+        }
+        catch
+        {
+            (window as any).__nitroClientMode = JSON5.parse(text);
+        }
         setBootDebug('boot: client-mode loaded');
     }
     catch(error)