feat: add Files Upload tab with manual file download request flow

- Add FilesUploadTab with a 4-step upload flow:
  `compute SHA-256 digest` → `fetch presigned PUT URL` →
  `upload to S3` →  `create FileDownloadRequest via GraphQL mutation`
- Add ManualFileDownloadRequestForm with destination, TTL, and
  progress fields validated via zod
- Add FileDownloadRequestsTable showing request history

Signed-off-by: Omar <omar.brbutovic@secomind.com>

Author: OmarBrbutovic

frontend/package-lock.json

@@ -33,6 +33,7 @@
     "class-variance-authority": "^0.7.1",
     "clsx": "^2.1.1",
     "dayjs": "^1.11.19",
+    "fflate": "^0.8.2",
     "graphql": "^16.9.0",
     "history": "^5.1.0",
     "js-cookie": "^3.0.5",
@@ -59,6 +60,7 @@
     "tailwind-merge": "^3.4.0",
     "tw-animate-css": "^1.4.0",
     "typescript": "^5.5.3",
+    "uuid": "^13.0.0",
     "vite": "^7.3.1",
     "vite-plugin-eslint": "^1.8.1",
     "vite-plugin-relay-lite": "^0.12.0",