The "email_already_claimed" tip in \`claim_via_otp\` (Python + Node)
referenced a \`mem0 link <key>\` command that doesn't exist. Real users
hit this dead end when they had a dashboard account predating their
agent's signup.
Replace with honest copy: "Sign in at app.mem0.ai with your existing
credentials." No promise of merging — that flow isn't built yet
(deferred design in platform repo .plans/).
Folded into this docs-promo PR rather than a separate small CLI PR
since it's user-facing wording.
Companion platform fix: mem0ai/platform#2790 (backend error messages
that suggested the same non-existent command).
Mgeeeek
879367f993