fix: switch to Lasso regression for better axis stability
- Replace Ridge with Lasso (L1) regression to concentrate weights on
fewer dimensions, improving stability measurement
- Default alpha changed to 0.1 (Lasso needs smaller values than Ridge)
- Fix dimension alignment issues in semantic drift and centroid computation
- Add dimension alignment in compute_semantic_drift and _generate_report
Results with Lasso alpha=0.1:
- 9/10 axes now stable (>0.7): [1, 2, 3, 4, 5, 7, 8, 9, 10]
- Axis 6 reordered (0.25-0.5 range)
- Axis 8 shows inflection points in 2016→2017→2018
- Overtone shift detected on all stable axes (1.3-1.9 range)
sgeboers
afdfe298cd