Bump aiohttp from 3.11.18 to 3.12.14 in /src/backend

Bumps [aiohttp](https://github.com/aio-libs/aiohttp) from 3.11.18 to 3.12.14.
- [Release notes](https://github.com/aio-libs/aiohttp/releases)
- [Changelog](https://github.com/aio-libs/aiohttp/blob/master/CHANGES.rst)
- [Commits](aio-libs/aiohttp@v3.11.18...v3.12.14)

---
updated-dependencies:
- dependency-name: aiohttp
  dependency-version: 3.12.14
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

src/backend/requirements.txt

@@ -2,7 +2,7 @@
 #    uv pip compile pyproject.toml -o requirements.txt --python-version 3.10
 aiohappyeyeballs==2.4.4
     # via aiohttp
-aiohttp==3.11.18
+aiohttp==3.12.14
     # via fastapi-app (pyproject.toml)
 aiosignal==1.3.1
     # via aiohttp