Update outdated dependencies and add Dependabot

[MateoLostanlen]

Most dependency pins are well behind current releases, and unlike pyro-api this repo has no bot keeping them fresh.

Current state vs latest

Package	Pinned	Latest
fastapi (camera API)	>=0.110,<0.111	0.141.1
uvicorn (camera API)	>=0.30,<0.31	0.52.4
numpy (camera API)	>=1.26.4,<2	2.5.3
huggingface_hub	==0.23.1	1.30.0
pillow (predictor)	==11.0.0	12.3.0
onnxruntime	==1.22.1	1.29.0
ncnn	==1.0.20240410	1.0.20260526
opencv-python-headless	<4.12	5.0.0.93
pytest	>=7,<8	9.1.1
mypy	>=1.9,<2	2.3.1
ruff	>=0.14,<0.15	0.16.6

Proposed work

1. Bump ranges in the 4 pyproject files (root, pyro_camera_api, pyro_camera_api/client, pyro-predictor) and align duplicate pins across them.
2. Drop redundant tooling from dependency groups: black, isort, flake8, pydocstyle (Makefile and CI only use ruff + mypy), and pytest-asyncio (no async tests).
3. Regenerate uv.lock and requirements.txt (uv export command in its header), run make quality + pytest.
4. Add .github/dependabot.yml like pyro-api, but simpler: uv + github-actions + docker ecosystems, weekly, grouped PRs, no allowlist.

Risks

• opencv 5.x, numpy 2.x, ncnn 2026 build and huggingface_hub 1.x are only covered by the test suite here; a smoke test on a Pi is needed before deploying.
• Base images are left untouched (camera API is on python:3.9.16-slim); the Dependabot docker ecosystem will propose those bumps separately.