Every technique_id in TechniqueBar and TTPInspector now links to its
canonical attack.mitre.org page. The inspector drawer gains a GROUPS
subpanel that lazy-fetches the new /ttp/techniques/{id}/groups endpoint
and renders each MITRE-tracked intrusion-set with deeplink and aliases.
Centralizes TTP row interfaces into src/types/ttp.ts and API wrappers
into src/utils/ttpApi.ts to give the new GroupRef type a clean home and
avoid a third inline fetch declaration.