chore(deps): bump the uv group across 1 directory with 2 updates

Bumps the uv group with 2 updates in the /backend directory: [cryptography](https://github.com/pyca/cryptography) and [aiohttp](https://github.com/aio-libs/aiohttp).


Updates `cryptography` from 48.0.1 to 50.0.0
- [Changelog](https://github.com/pyca/cryptography/blob/main/CHANGELOG.rst)
- [Commits](pyca/cryptography@48.0.1...50.0.0)

Updates `aiohttp` from 3.14.1 to 3.14.3
- [Changelog](https://github.com/aio-libs/aiohttp/blob/master/CHANGES.rst)
- [Commits](aio-libs/aiohttp@v3.14.1...v3.14.3)

---
updated-dependencies:
- dependency-name: cryptography
  dependency-version: 50.0.0
  dependency-type: direct:production
  dependency-group: uv
- dependency-name: aiohttp
  dependency-version: 3.14.3
  dependency-type: indirect
  dependency-group: uv
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

backend/pyproject.toml

@@ -25,7 +25,7 @@ dependencies = [
     "aioboto3>=15.5.0",
     "fastapi-users[sqlalchemy]>=14.0",
     "slowapi>=0.1.9",
-    "cryptography>=48.0.1",
+    "cryptography>=50.0.0",
     # Cap <8: redis-py 8 defaulted the protocol to RESP3, which exposes
     # an async-only fakeredis bug — `_decode` doesn't recurse into dicts,
     # so `FakeRedis(decode_responses=True).hgetall(...)` returns bytes