restore(mobile): restore mobile/ directory to pre-d2217531 state

Restored mobile/ from d22175310a711e7ebdd8062ae29a54f0136dc3f6^
(parent commit d94e9ca4bc).

Commit d22175310a (google-labs-jules[bot], 2026-03-23T14:45:22Z) introduced
an SSRF security fix for IMAP connections but unintentionally deleted or
truncated a large number of files across the repository, including 24 files
under mobile/.

This commit targets only the mobile/ directory and restores the following
files to their pre-d2217531 state:

- mobile/README.md
- mobile/app.json
- mobile/app/(tabs)/_layout.tsx
- mobile/app/(tabs)/file-detail.tsx  (re-added)
- mobile/app/+not-found.tsx          (re-added)
- mobile/app/_layout.tsx
- mobile/eslint.config.js            (re-added)
- mobile/package-lock.json
- mobile/package.json
- mobile/src/context/ShareContext.tsx
- mobile/src/i18n/de.json            (re-added)
- mobile/src/i18n/en.json            (re-added)
- mobile/src/i18n/es.json            (re-added)
- mobile/src/i18n/fr.json            (re-added)
- mobile/src/i18n/index.ts           (re-added)
- mobile/src/i18n/it.json            (re-added)
- mobile/src/screens/FileDetailScreen.tsx (re-added)
- mobile/src/screens/FilesScreen.tsx
- mobile/src/screens/LoginScreen.tsx
- mobile/src/screens/ProfileScreen.tsx
- mobile/src/screens/UploadScreen.tsx
- mobile/src/screens/WelcomeScreen.tsx
- mobile/src/services/api.ts
- mobile/src/utils/mimeTypes.ts      (re-added)
- mobile/src/utils/normalizeUri.ts   (re-added)

Security fixes introduced by d2217531 that are unrelated to mobile/
(IMAP SSRF fix in app/utils/network.py and app/tasks/imap_tasks.py)
are preserved — this restore targets only files under mobile/.

mobile/src/context/ShareContext.tsx

@@ -9,6 +9,7 @@
  */
 
 import React, { createContext, useCallback, useContext, useState } from "react";
+import { normalizeFileUri } from "../utils/normalizeUri";
 
 export interface SharedFile {
   uri: string;
@@ -32,7 +33,13 @@ export function ShareProvider({ children }: { children: React.ReactNode }) {
   const [pendingFiles, setPendingFiles] = useState<SharedFile[]>([]);
 
   const addPendingFile = useCallback((file: SharedFile) => {
-    setPendingFiles((prev) => [...prev, file]);
+    setPendingFiles((prev) => {
+      // Deduplicate by normalised URI so the same file is not uploaded twice
+      // when both the Linking handler (_layout.tsx) and +not-found.tsx fire.
+      const norm = normalizeFileUri(file.uri);
+      if (prev.some((f) => normalizeFileUri(f.uri) === norm)) return prev;
+      return [...prev, file];
+    });
   }, []);
 
   const clearPendingFiles = useCallback(() => {