cleanup opportunities dead ends

Dead ends

These references are weak or dead. "Confirmed unused" means no importer exists in the capsule. "Legacy web-era surface" means the code was live before the migration and is no longer mounted.

File	Status	Evidence
lib/utils.ts	Confirmed unused	Exports cn; a search for lib/utils returns no importers in the capsule
lib/desktop/product-surface.ts	Confirmed unused	No importers; a compiled sibling lib/desktop/product-surface.js also exists
lib/transform/storage.ts	Legacy web-era surface	Writes transform history to localStorage; no callers in the capsule
lib/embeddings/similarity.ts	Partly unused	cosineSimilarity is used by lib/templates/matcher.ts; findSimilarPrompts is defined but never called
RecommendRequest / RecommendResponse in types/index.ts	Confirmed unused	Schemas and inferred types are defined; no consumer
lib/supabase/server.ts, middleware.ts, browser.ts	Confirmed unused	No importers; the desktop shell uses public.ts, admin.ts, and action.ts

Two notes on the boundary. lib/supabase/action.ts is live: lib/auth/require-current-user.ts imports createSupabaseActionClient, and that module is reached from desktop/ipc/core.ts. And the localStorage history in lib/transform/storage.ts is the clearest example of web-era code: history was a browser feature, and the desktop shell keeps drafts and recent runs through the workspace store instead.