feat: add LinkSnappy provider, account deactivation, UI polish

- Add LinkSnappy provider with cookie-based session auth and /api/linkgen
- Upgrade LinkSnappy download URLs from http to https (fix 425 errors)
- Add account deactivation toggle (disabledProviders in settings)
- Show account type (API/Web/Login) in provider dropdowns
- Show API key count for Debrid-Link in status label
- Fix all missing German umlauts throughout the UI
- Wider modal for textarea, compact action buttons in one row
- Debrid-Link: log which API key (#1/#2) is used for unrestrict

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/main/constants.ts

@@ -53,6 +53,8 @@ export function defaultSettings(): AppSettings {
     ddownloadPassword: "",
     oneFichierApiKey: "",
     debridLinkApiKeys: "",
+    linkSnappyLogin: "",
+    linkSnappyPassword: "",
     archivePasswordList: "",
     rememberToken: true,
     providerPrimary: "realdebrid",
@@ -95,6 +97,7 @@ export function defaultSettings(): AppSettings {
     bandwidthSchedules: [],
     columnOrder: ["name", "size", "progress", "hoster", "account", "prio", "status", "speed"],
     extractCpuPriority: "high",
-    autoExtractWhenStopped: true
+    autoExtractWhenStopped: true,
+    disabledProviders: []
   };
 }