docs(mobile-phone-waterfall): add plan availability note for trial users

[george-dilthey]

What changed

Added a plan availability note to docs/mobile-phone-waterfall.md — one sentence before the setup steps stating that the Mobile Phone waterfall requires a Launch plan or higher and is not available on free or trial plans.

Why

An Intercom ticket (conversation #215475571632835) was flagged where a trial user asked about mobile/direct-line phone enrichment and discovered it wasn't available. Fin and the human agent (Aamish Samotra) both correctly answered that phone enrichment requires a paid plan — but the answer came from plans-and-billing.md and building-a-data-waterfall.md, not from the Mobile Phone waterfall doc itself.

mobile-phone-waterfall.md had zero mention of plan restrictions. A trial user reading this page for setup instructions would receive complete how-to steps with no warning they'd be blocked from using it. This creates a Fin retrieval failure: if a trial user asks "how do I use the Mobile Phone waterfall?", Fin retrieves this page and gives setup instructions without the critical restriction.

The restriction is already correctly documented in:

• plans-and-billing.md lines 56 and 150–152
• building-a-data-waterfall.md lines 173–183 (which says "Providers that can return phone numbers — such as PDL (People Data Labs), Bytemine, and others — require the Launch plan or higher")

Source link(s)

• Intercom conversation: https://app.intercom.com/a/inbox/_/inbox/conversation/215475571632835
• Verifier verdict: PASS — phone number enrichment requires Launch plan or higher; confirmed against existing documentation in plans-and-billing.md and building-a-data-waterfall.md

Uncertainties

None. The plan restriction is explicitly documented in two other docs and confirmed by the verifier sub-agent.

Related observations

The mobile-phone-waterfall.md doc could also note the workaround for trial users who want partial waterfall functionality (remove phone-number providers from the sequence), but building-a-data-waterfall.md already covers that at lines 183–184. Cross-linking is handled by the reference to plans-and-billing.md#trials in the added note.

Closes DOC-2041

[linear-code]

DOC-2041