Scrub legacy blinding vocabulary (pre-Smokescreen blind A/B/C)

Three pre-Smokescreen "blind" strata survive in the code and collide with Smokescreen blinding (#241) vocabulary:

• CosmologyValidation.blind — redshift-path blind A/B/C suffix substitution (core.py)
• the blind wildcard on the pseudo_cl rules — glass-mock A/B/C variant, baked into on-disk filenames (kept as-is in #251 by ruling; comments mark the distinction)
• blind=A_… tags in legacy product filenames

Scrub them once the SACC/blinding stack (#251/#253/#255) is merged — this gates the first real assembly run, so no real product is made while two blinding vocabularies coexist: retire the legacy catalogue-blind path, rename or retire the mock-variant wildcard where on-disk compatibility allows, and unify stem/wildcard construction so every pseudo-Cl variant uses the same path-building convention (the new pseudo_cl_analysis stem currently differs from the wildcarded mock rules). Deliberately out of scope for #251/#253.

— Claude (fable) on behalf of Cail.

Start in core.py at CosmologyValidation.blind, then trace the pseudo_cl rules and legacy product filename tags. Compare the pseudo_cl_analysis stem with the wildcarded mock-rule construction and check the compatibility constraints from #251/#253/#255. Done means the legacy catalogue-blind path and permitted mock-variant vocabulary are retired or renamed, with one consistent pseudo-Cl path convention.