Honor include_dev_requirements flag in Uv.install()

[Copilot]

The include_dev_requirements parameter in Uv.install() was accepted but ignored, making it impossible to control whether dev dependencies were installed.

Changes:

• Pass --no-dev to uv sync when include_dev_requirements=False (default)
• Added test_install_with_dev() to verify flag behavior

Behavior:

uv.install()                              # uv sync --no-dev (excludes dev)
uv.install(include_dev_requirements=True) # uv sync (includes dev)

This matches Poetry's semantic interface where the flag controls dev dependency installation.

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