eql-v3-sole-docs.md

stash	patch
@cipherstash/stack	patch

Docs: EQL v3 is now the sole documented approach. The stash-encryption, stash-drizzle, and stash-supabase skills and the @cipherstash/stack README teach only the v3 typed surface (Encryption, the types.* concrete domains, the @cipherstash/stack-drizzle package root, encryptedSupabase); EQL v2 shrinks to one short Legacy section per document. Two places keep more than a Legacy section, because EQL v2 is still reachable there:

• DynamoDB reads. encryptedDynamoDB writes EQL v3 only, but decryptModel / bulkDecryptModels still accept an EQL v2 table so previously stored v2 items stay readable, so the stash-dynamodb skill keeps the v2 schema shape documented for that read path (#657).
• The encrypt rollout lifecycle. stash encrypt * and @cipherstash/migrate detect a column's generation from its Postgres domain type, with EQL v3 as the recognised and default generation; a legacy eql_v2_encrypted column does not classify and falls through to the v2 lifecycle, which ends in stash encrypt cutover rather than the v3 stash encrypt drop. That difference is kept under a version callout (#648).

Also corrects the legacy @cipherstash/drizzle README's pointer to the removed @cipherstash/stack/drizzle subpath (now the separate @cipherstash/stack-drizzle package).