fix(models): price Hermes lowercase glm-5.2 the same as GLM-5.2

[ozymandiashh]

Follow-up to the maintainer's note on #543. The merged Hermes provider (#544) reads sessions.model and passes it straight to calculateCost, but Hermes stores GLM-5.2 lowercased as glm-5.2, while BUILTIN_ALIASES only carries the capitalized GLM-5.2 (added for ZCode). As a result GLM-5.2 sessions logged by Hermes resolve to no pricing and report €0.

This adds the lowercase glm-5.2 alias pointing to the same glm-5p1 sibling, plus a regression test asserting the lowercase and capitalized spellings price identically. Verified against a real ~/.hermes/state.db whose only GLM model id is glm-5.2.