[IMPROVEMENT] Extend favorites to cycles/modules with folders and ordering

[martian56]

Type / Priority

Improvement / Medium

Summary

Favorites cover only projects/views/pages and lack folders and ordering; cycles and modules can't be favorited server-side.

Current state (evidence)

• Router favorites cover only projects, views, pages (router.go:241,281-282,361-390). model/user_favorite.go has no is_folder/parent/sequence fields. No cycle/module favorite routes; the cycle/module favorite hooks are localStorage-only (useCycleFavorites.ts, useModuleFavorites.ts).
• (Distinct from [BUG] Sidebar favorites re-fetch every project's modules/cycles on any change (N+1) #143's N+1 perf bug and [SECURITY] Recent-visits records/reflects unvalidated cross-workspace entity IDs (IDOR) #156's IDOR.)

Proposed scope

Add cycle + module favorite entity types (server-persisted); add is_folder+parent_id+sort_order columns + migration; folder CRUD + reorder endpoint; a sidebar favorites tree.