fix: stamp source builds above every intra-family dep floor

setup.py fell back to "1.0.dev0" when VERSION is unset, which is what any
source install does. That sorts BELOW every date release, so a local checkout
advertised itself as older than a 2022 wheel. Harmless while nothing in the
family constrained a sibling; fatal once the >=2026.7.29.2 floors landed
(PyAutoLens#687), since 1.0.dev0 cannot satisfy them and pip raises
ResolutionImpossible.

The same defect was already biting silently: three *_workspace_test repos
carry `pip install --force-reinstall --no-deps ./PyAutoNerves` because the
[optional] re-resolution kept pulling the stale PyPI autonerves over the
local build. The floors turned silent into loud.

"9999.0.0.dev0" sorts above every date release (satisfies present and future
floors), keeps .dev so nothing claims the checkout is a release, and is not
read by the autonerves workspace handshake (that reads __version__).

Refs PyAutoLabs/PyAutoNerves#146.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JJA22BPEreojsu7LZHFwsv

Author: 2 people

setup.py

@@ -1,7 +1,11 @@
 import os
 from setuptools import setup
 
-version = os.environ.get("VERSION", "1.0.dev0")
+# Source builds stamp a version ABOVE every date release. Intra-family deps
+# carry `>=` floors, so a low dev stamp (the old "1.0.dev0") makes a local
+# checkout unsatisfiable against its own siblings. Release builds always set
+# VERSION explicitly, so this default is never published.
+version = os.environ.get("VERSION", "9999.0.0.dev0")
 
 setup(
     version=version,