refactor: remove localStorage persistence from tokenStore to enforce in-memory session management

src/auth/tokenStore.ts

@@ -2,38 +2,14 @@ export type StoredTokens = {
     access_token: string;
 };
 
-const LS_KEY = "uhm_auth_tokens_v1";
-
 let cached: StoredTokens | null = null;
 
-function safeParseTokens(raw: string | null): StoredTokens | null {
-    if (!raw) return null;
-    try {
-        const v = JSON.parse(raw) as Partial<StoredTokens>;
-        if (!v || typeof v !== "object") return null;
-        if (typeof v.access_token !== "string") return null;
-        if (!v.access_token.trim()) return null;
-        return { access_token: v.access_token };
-    } catch {
-        return null;
-    }
-}
-
 export function getStoredTokens(): StoredTokens | null {
-    if (cached) return cached;
-    if (typeof window === "undefined") return null;
-    cached = safeParseTokens(window.localStorage.getItem(LS_KEY));
     return cached;
 }
 
 export function setStoredTokens(tokens: StoredTokens | null): void {
     cached = tokens;
-    if (typeof window === "undefined") return;
-    if (!tokens) {
-        window.localStorage.removeItem(LS_KEY);
-        return;
-    }
-    window.localStorage.setItem(LS_KEY, JSON.stringify(tokens));
 }
 
 export function getAccessToken(): string | null {