ctx journal site --build fails silently with macOS system Python (zensical requires Python >= 3.10)

[v0lkan]

Summary

ctx journal site --build and --serve fail when zensical is installed via the system/Xcode Python (3.9) because PyPI installs a stub placeholder (v0.0.2) instead of the real package. The error message suggests pip install zensical which doesn't fix the problem.

Steps to Reproduce

1. macOS with default Python 3.9 (Xcode Command Line Tools)
2. pip3 install zensical — reports success (installs v0.0.2 stub)
3. ctx journal site --build — fails with Error: zensical not found

Expected Behavior

Either:

• The error message should mention the Python >= 3.10 requirement and suggest pipx install zensical or brew install pipx && pipx install zensical
• Or ctx journal site --help / docs should document the prerequisite clearly

Actual Behavior

$ pip3 install zensical
Requirement already satisfied: zensical in /Users/.../Python/3.9/lib/python/site-packages (0.0.2)

$ which zensical
zensical not found

$ ctx journal site --build
Error: zensical not found. Install with: pip install zensical

The stub package (v0.0.2) has an empty __init__.py and no CLI entry point. The real package (v0.0.21) requires Python >= 3.10.

Workaround

brew install pipx
pipx install zensical
ctx journal site --build  # works

Suggestion

Update the error message in ctx journal site from:

Error: zensical not found. Install with: pip install zensical

To something like:

Error: zensical not found. Install with: pipx install zensical
(requires Python >= 3.10; macOS system Python 3.9 installs a non-functional stub)

Environment

• ctx: v0.3.0
• macOS (Darwin 25.2.0, arm64)
• System Python: 3.9 (Xcode Command Line Tools)