[Automate][ELITEA-1791] `~` mention in Agent instructions lists only currently attached Skills

[bermudas]

Source case: tests/automated-full-regression-ui/skills/ELITEA-1791_tilde-mention-lists-only-attached-skills.md
(https://github.com/EliteaAI/onetest-ai-tm-Elitea/blob/main/tests/automated-full-regression-ui/skills/ELITEA-1791_tilde-mention-lists-only-attached-skills.md)

Metadata

• id: ELITEA-1791
• module: skills
• priority: medium
• type: functional
• status: draft
• execution_type: manual
• automation_test_id: (none)

Filed by Tal's cardless intake sweep — not yet triaged/approved. A human should drag this card to confirm before an analyst dispatch picks it up.