Migrate development workflow to uv lockfile (#2016)

* Migrate development workflow to uv lockfile

* Address dependency workflow review feedback

* update lockfile

* pin python version for extras-no-video

* rework the make targets and workflows

* move to v9.0.0 instead of v9 for astral uv setup

* lower bounds for dependency groups

* fix: raise minimal setuptools floor to 56 for py3.8 test collection

lowest-direct pulled setuptools 21, too old for the find_spec pytest's
importlib mode calls. 56 is the first release with it, still under torch
1.10's cap of 60.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* fix: floor numpy to 1.21 in minimal group for numpy.typing.NDArray

The newest Pillow the lowest-direct resolver selects imports
numpy.typing.NDArray, which numpy added in 1.21.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* fix: drop removed lightly-download from test-cli smoke test

master's API client removal deleted the lightly-download entry point.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* fix: cap minimal setuptools at <59.6 for torch 1.10 distutils.version

The <60 cap still admitted 59.8. setuptools 59.6 changed its distutils
hook so torch 1.10's tensorboard import fails on distutils.version;
59.5.0 is the last release that works.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* fix: run lock-check before install-maximal so CI catches a stale lock

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* chore: drop dead API-only targets and fix stale dev-workflow docs

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* build: skip PyAV system deps outside CI and run mypy hook via uv

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* ci: run tests and type-check on 3.8/3.12, drop dead server env

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* build: drop redundant av python marker and refine dep comments

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* ci: run maximal test and type-check on 3.12 only

Maximal deps (torch 2.5.1) have no cp38 wheels; 3.8 is covered by the minimal-deps workflow.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

---------

Co-authored-by: Lionel Peer <lionel@lightly.ai>
Co-authored-by: gabrielfruet <gabrielfruet538@gmail.com>
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>