Rename docs/research/extractions to distilled #45

Problem

The folder docs/research/extractions holds distilled Tier-2 rules, but in Evermore 'extraction' means retrieving data out of a shelter system. The name collides with settled vocabulary.

Proposed solution

Rename docs/research/extractions to docs/research/distilled and update references.

Acceptance Criteria

• The folder is renamed to distilled.
• All references (docs, code, READMEs) are updated.
• The terminology note in docs/CLAUDE.md is reconciled.