CI uses pip install while Makefile uses uv sync

[gkorland]

Description

There is an inconsistency between CI and local development tooling:

CI workflows use pip:

• .github/workflows/nextjs.yml: pip install -e ".[test]"
• .github/workflows/playwright.yml: pip install -e .

Makefile uses uv:

• make install: uv sync --all-extras
• make test: uv run python -m pytest
• make run-dev: uv run flask ...

This can lead to different dependency resolutions and hard-to-reproduce CI failures.

Suggested Fix

Align CI workflows with the Makefile by using uv in CI:

- run: pip install uv
- run: uv sync --all-extras

Context

Found during code review of PR #522.