Improve NIP-98 error messages and disable nostrimg.com by default

**Motivations:**
- Provide clearer error messages when NIP-98 authentication is not available
- Disable nostrimg.com by default since it returns server errors (500)
- Help users understand why nostrcheck.me endpoint is skipped

**Root causes:**
- NIP-98 authentication requires unlocked account but error message was generic
- nostrimg.com endpoint consistently returns 500 errors
- Users don't understand why nostrcheck.me is skipped

**Correctifs:**
- Added detailed error messages for NIP-98 unavailability:
  - No account: 'Please create or import an account'
  - Account not unlocked: 'Please unlock your account with your recovery phrase'
- Disabled nostrimg.com by default (enabled: false) due to server errors
- Improved console warnings with specific reasons for skipping endpoints

**Evolutions:**
- None

**Pages affectées:**
- lib/nip95.ts
- lib/configStorageTypes.ts

lib/configStorageTypes.ts

@@ -42,7 +42,7 @@ export const DEFAULT_NIP95_APIS: Nip95Config[] = [
   {
     id: 'nostrimg',
     url: 'https://nostrimg.com/api/upload',
-    enabled: true,
+    enabled: false, // Disabled by default due to server errors (500)
     priority: 1,
     createdAt: Date.now(),
   },

lib/nip95.ts

@@ -1,6 +1,8 @@
 import type { MediaRef } from '@/types/nostr'
 import { getEnabledNip95Apis } from './config'
 import { generateNip98Token, isNip98Available } from './nip98'
+import { nostrService } from './nostr'
+import { nostrAuthService } from './nostrAuth'
 
 const MAX_IMAGE_BYTES = 5 * 1024 * 1024
 const MAX_VIDEO_BYTES = 45 * 1024 * 1024
@@ -131,7 +133,15 @@ export async function uploadNip95Media(file: File): Promise<MediaRef> {
 
       if (needsAuth) {
         if (!isNip98Available()) {
-          console.warn('NIP-98 authentication required for nostrcheck.me but not available. Skipping endpoint.')
+          const pubkey = nostrService.getPublicKey()
+          const isUnlocked = nostrAuthService.isUnlocked()
+          if (!pubkey) {
+            console.warn('NIP-98 authentication required for nostrcheck.me but no account found. Please create or import an account.')
+          } else if (!isUnlocked) {
+            console.warn('NIP-98 authentication required for nostrcheck.me but account is not unlocked. Please unlock your account with your recovery phrase to use this endpoint.')
+          } else {
+            console.warn('NIP-98 authentication required for nostrcheck.me but not available. Skipping endpoint.')
+          }
           continue
         }
         try {