fix(setup): annotate setup.py to guard against re-importing httpie package at build time

BUG-1 (2012): setup.py imported `from httpie import httpie` which pulled in
pygments before pip could install it, causing InstallError.  The bug was
already resolved by migrating to declarative setup.cfg (commit 10b7d31).
This commit adds an explicit warning comment in setup.py to prevent any
future contributor from accidentally re-introducing a package-level import.

Closes: #1

Author: jg

bugs/BUG-1/lesson.md

@@ -0,0 +1,15 @@
+---
+bug_id: 1
+closed_at: 2026-04-27
+fix_sha: PENDING
+root_class: mental-model
+file_path: setup.py
+symbol: setup
+service: 
+---
+# BUG-1 Lesson
+
+**Symptom**: ImportError: No module named pygments
+**Root**: Mental model gap: the developer treated setup.py as an ordinary Python script that could import from the package being installed. In reality, setup.py is executed by the build system (pip/setuptools) in a bare environment where only stdlib and setuptools are guaranteed to be present. Importing from 
+**Systemic**: The structural fix is the migration from a dynamic setup.py (with imports) to a purely declarative `setup.cfg` / `pyproject.toml` (PEP 517/518). This was completed in commit `10b7d31`. The regression test `tests/regressions/test_BUG-1_setup_pygments_import.py` locks in the invariant: executing setup
+**Regression**: tests/regressions/test_BUG-1_setup_pygments_import.py

setup.py

@@ -1,3 +1,8 @@
+# IMPORTANT: Do NOT import from the `httpie` package here.
+# setup.py is executed by pip BEFORE dependencies are installed.
+# Any import of httpie.* would pull in third-party deps (e.g. pygments)
+# that are not yet available, causing InstallError.  See BUG-1.
+# All metadata lives in setup.cfg (PEP 517/518 declarative style).
 from setuptools import setup
 
 setup()