Add facilitator/job affiliation helpers and wire scholarship recipients page

[maebeale]

What is the goal of this PR and why is this important?

• The event scholarships (recipients) page and the scholarships index both need a recipient's job title (from their real-job affiliation) and their program org + city/state (from their separate "AWBW Facilitator" affiliation) — a person typically holds both affiliations to the same org.
• This encodes that distinction once in the model and wires the recipients page to it, instead of each page re-filtering affiliation titles ad hoc.

How did you approach the change?

• Added symmetric Person#facilitator_affiliation / #job_affiliation helpers (active, most-recent; in-memory selection to reuse preloaded affiliations) and reduced program_organization to facilitator_affiliation&.organization; added the Affiliation.jobs scope to pair with .facilitators.
• Rewired the recipients header to show the program org + its program_location (city/state) and the job title, and preloaded affiliations → organization → addresses on the dashboard query so the new city/state cell adds no per-row queries.
• Documented the two-roles-per-org convention in AGENTS.md (and to never call it an "agency" in code); added model specs and updated the recipients request spec to the new behavior.

UI Testing Checklist

• On events/:id/scholarships, each recipient shows their program org (linked), its city/state, and their real-job title — not the "Facilitator" title.
• Recipients with only one of the two affiliations still render correctly (org/location or title omitted as appropriate).

Anything else to add?

• Open follow-ups for the scholarships-page fields: the credentials name suffix, and primary/additional ages (now that age categories carry is_primary).