fix(web): skip empty Authorization header for forward-auth proxy compatibility

Centralize duplicated getToken() + Bearer header logic into a single
formatHeaders() helper in lib/api.ts. When no token exists, the
Authorization header is omitted entirely instead of sending an empty
Bearer token, which breaks forward-auth proxies like Authelia behind
Caddy.

Changes:
- Add formatHeaders() with try-catch around localStorage access
- Replace 20+ duplicated getToken() definitions across tool components
- Migrate all call sites including file-details, settings, change-password
- Update tests to verify header omission on empty token

Based on the fix proposed by @jules2689 in #6, with improvements:
file placement (lib/api.ts vs components), localStorage error handling,
simplified truthiness check, and complete call-site coverage.

Co-Authored-By: Julian Nadeau <julian@jnadeau.ca>

apps/web/src/hooks/use-auth.ts

@@ -1,4 +1,5 @@
 import { useEffect, useState } from "react";
+import { formatHeaders } from "@/lib/api";
 
 interface AuthState {
   loading: boolean;
@@ -45,7 +46,7 @@ export function useAuth(): AuthState {
         }
 
         const sessionRes = await fetch("/api/auth/session", {
-          headers: { Authorization: `Bearer ${token}` },
+          headers: formatHeaders(),
         });
 
         if (sessionRes.ok) {