Adds a PetAvatar wrapper (hash(name) mod 360 -> HSL background) and
migrates the four most-visible avatar call sites (sidebar, mobile nav,
post card, post detail incl. comments) to use it instead of duplicated
inline initials logic.
Desktop sidebar can now collapse to an icon-only 76px rail, persisted
in localStorage (same client-init pattern as ActivePetContext). All
nav rows, the new-post button, and the owner row adapt; secondary
sections (language switcher, legal footer) hide when collapsed.
Gitea #12, #14
admin
5fbf39593d