Give guests a weather-aware event preparation brief

[KalebCole]

User scenario

I am going to an outdoor movie night tomorrow. Before I leave, I want one CLI brief that says when it is, what location precision I am allowed to see, and the forecast for that place and time, so I can dress appropriately without accidentally revealing a private address.

Problem

events get provides event details, and #60 documents that guest locations may be approximate by design. The CLI has no preparation workflow that combines permitted location information with a clearly sourced external forecast, so guests must manually transfer event details into another service.

Proposed experience

partiful events conditions <eventId>
partiful events conditions <eventId> --days 2 --format json

Human output shows event timing, the permitted venue or approximate area, forecast source/time, and a compact preparation-oriented summary. JSON output keeps event data separate from forecast data, includes precision and freshness metadata, and reports when a forecast cannot be safely resolved. It should never display a more precise location than the event read exposed.

Scope boundaries

Read-only. Do not geocode hidden addresses, reveal coordinates, track a guest, alter event details, or present weather as a safety guarantee. A forecast provider is external to Partiful and must be clearly attributed.

Discovery needed

Verified repo facts: event detail reads exist; #60 verified locationInfo can contain either full address lines or only an approximate location for guests. Unknown: whether a supported weather provider can safely forecast from the permitted display location, required attribution/rate-limit rules, and how to handle ambiguous venues. Investigate provider capability separately; do not invent a Partiful weather endpoint.

Acceptance criteria

• The command uses no location precision beyond what the caller is authorized to view.
• Human output labels forecast source, retrieval time, forecast horizon, and location precision.
• JSON separates Partiful event fields from external forecast fields and includes null/unknown resolution states.
• Indoor, missing-location, ambiguous-location, and out-of-range-date cases are explicit successful or structured-error outcomes.
• If no usable forecast can be produced, human output says so plainly and JSON returns a successful empty forecast state with a machine-readable reason.
• Provider failures do not suppress the event details and never fabricate a forecast.
• Tests cover exact versus approximate locations, no location, provider timeout/error, stale data, privacy redaction, and JSON output.

Related work

#60 fixes reliable display of guest-safe location data; this consumes only that permitted display layer and adds a separate preparation outcome. #18 analyzes events, while this helps one guest prepare for one upcoming event.