WillTools 2026-09-09 -- clean snapshot of the development repo for review

History-free snapshot of the private development repository at cbe45c5
(2026-09-09). Code, docs and public catalogue only; no plant or job
knowledge layers, no client or job names (tools/scrub.py clean). The
intro deck is left out of this snapshot because its slide images could
not be checked for job drawings.

beamcalc/tests/conftest.py

@@ -0,0 +1,16 @@
+# -*- coding: utf-8 -*-
+"""Put beamcalc/src first on sys.path. Run from the repo root, the bare
+`beamcalc/` directory (which holds fixtures/, tools/, tests/ and src/) is
+what `import beamcalc` finds -- an implicit namespace package with no
+modules in it -- and every test here fails to import. `pip install -e
+beamcalc` would fix it too, but the suite must run on a fresh checkout
+with nothing installed, same as the rest of this repo."""
+import os
+import sys
+
+_SRC = os.path.join(os.path.dirname(os.path.dirname(os.path.abspath(__file__))), 'src')
+if _SRC not in sys.path:
+    sys.path.insert(0, _SRC)
+_mod = sys.modules.get('beamcalc')
+if _mod is not None and getattr(_mod, '__file__', None) is None:
+    del sys.modules['beamcalc']  # the namespace-package placeholder