chore(dev): Move from pip compile/install to uv sync

[Twixes]

Problem

requirements.txt is the barbarian's way of managing dependencies – no locking, no clear way to handle dev dependencies, while pyproject.toml is the modern (and PEP-approved) format for dependencies.

Its simplest to use with uv. The uv sync command does it all:

1. If a virtual environment is missing, it creates it under .venv/, even installing the right version of Python if it's specified with --python.
2. Resolves all dependency versions and updates the uv.lock lockfile if anything has changed.
3. Installs (and upgrades/downgrades) installed dependencies based on the lockfile. In production, you skip dev dependencies using --no-dev.

Changes

Moved all the deps into pyproject.toml. requirements{,-dev}.{txt,in} are no more.
Moved to uv sync across: Dockerfiles, Actions workflows, Flox activation. pip install is no more.

[greptile-apps]

PR Summary

Overall, this PR transitions dependency management from the legacy requirements.txt system to a modern, lockfile-based approach using pyproject.toml and uv sync across development, CI, and Docker environments.

• Updated .devcontainer/Dockerfile and Dockerfile to install uv and run "uv sync" with proper flags.
• Modified multiple GitHub workflows (e.g., .github/workflows/ci-backend.yml, benchmark.yml, and ci-turbo.yml) to use "uv sync --frozen" and highlighted potential caching issues.
• Adjusted dependency guidelines in .cursor/rules/django-python.mdc to recommend "uv sync" and "uv add PACKAGE".
• Removed legacy dependency files (requirements.txt, requirements.in, requirements-dev.txt).

_{23 file(s) reviewed, 2 comment(s)
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[github-actions]

Size Change: +6 B (0%)

Total Size: 9.96 MB

ℹ️ View Unchanged

Filename	Size	Change
frontend/dist/toolbar.js	9.96 MB	+6 B (0%)

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[mariusandra]

If you get this working and passing tests, then you have my blessing

[pauldambra]

shall we increase this?
i guess you could argue not to change too much until we get it working but 3.8 🤯

[Twixes]

Here the version actually doesn't matter, because it's just for running the HobbyTester Python script, and the actual deployment all happens in a remote DigitalOcean droplet

[pauldambra]

well, i will be happy to stop looking up the pip compile command every time i need it 😅 🚀

once CI is green we should smash this in

[Twixes]

The two test failures are expected:

1. Validate Django and CH migrations - this first installs PostHog as it is on master, now using uv sync, but master doesn't have a uv.lock yet. A chicken and egg problem that goes away with merging this
2. Setup DO Hobby Instance and test - this hasn't been passing for a while due to unrelated issue in the hobby deploy (internal Slack thread)