tidy

src/ws/diff.py

@@ -0,0 +1,12 @@
+"""Weight-space diff: w = θ+ - θ-.
+
+Functional replacement for the original TaskVector class.
+
+Approach: load the +/- adapters, merge each into a delta state-dict over the
+base model (delta = merged - base), then subtract:
+    w_layer = delta_pos[layer] - delta_neg[layer]
+
+Merging into delta-W space (rather than diffing in adapter A/B space) makes
+all adapter families comparable downstream - LoRA, DoRA, PiSSA-init, DeLoRA
+all produce a delta in W's space.
+"""