Places — every city is a foreign key; venues carry a structured address

Context

• City is free text or a slug everywhere. Free-text name columns: dancers.city, profiles.city, events.city, festivals.city, gigs.location, festival_ride_shares.origin_city. Slug columns with no reference: profiles.city_slug, events.city_slug, city_videos, video_votes, giveaways, reviews, community_groups, recommendation_requests, hangouts, city_battle_votes (both sides). Production has 585 distinct spellings across them, with four spellings of Munich in seven gigs rows (docs/research/2026-10-12-city-canonicalisation.md:20-60).
• The cities table is referenced by nothing (schema.ts:739-759) and is not in production yet (city-canonicalisation.md:18).
• Matching is by string. plan.discover derives a slug from free text (plan.ts:483-484) and matches dancers with ilike (plan.ts:533); /artists?city= compares profiles.city strings (RAZ-64 notes); "Real numbers" counts profiles per city_slug (RAZ-47).
• Audience geography cannot be computed (RAZ-85): dancers.city is free text.
• Venue address is a single text field (profiles.address, schema.ts:316) while events carry their own venue_name, venue_address, venue_lat, venue_lng (schema.ts:630-633). Venue filters for event planners need amenities that do not exist (RAZ-302).
• A detailed, already-reviewed plan exists for the city part: docs/research/2026-10-12-city-canonicalisation.md §Plan (7 steps).

Options

1. Keep slugs as the key and canonicalise slug spelling. Cheap, but a slug is derived from a name, so renames and alternative spellings keep breaking identity, and nothing enforces that a slug exists.
2. city_id foreign keys to the Google-Places-backed cities table, slugs only as URL keys joined from cities.slug.
3. A general places table (cities, venues, addresses as one hierarchy). Flexible, but venues are already profiles with pages, members and bookings; a second venue entity would split them again.

Decision

Option 2 for cities, exactly as the canonicalisation plan lays out (apply 0024, backfill cities, add nullable city_id columns, fill, dual-write, switch reads, drop the text columns last with separate approval). This ADR adds the venue part:

• Venue = profiles row with type = 'venue' (no new entity). Its address becomes structured: address_line, postal_code, city_id, country_code, lat, lng, google_place_id (unique where not null; it is already the v4 venue-handle convention used by the v3 sync dedupe, CLAUDE.md "Profiles (since 0022)"). address (free text) stays as the display line until reads move.
• Events reference the venue by FK (events.venue_profile_id, ADR-006). The venue_name/address/lat/lng columns on events remain as a snapshot for events whose venue has no profile (v3 rows the sync could not match).
• Amenities and floors are vocabularies. profiles.amenities text[] (bar, stage, sound system, changing room, parking, step-free access, …) and floor_type constrained to wood · parquet · vinyl · tiles · concrete · other, on both venues and bookable_spaces. GIN index on amenities for the /venues filters.
• Every city-scoped table gets city_id (including hangouts, community_groups, giveaways, city_videos, video_votes, recommendation_requests, reviews, city_battle_votes.winner_city_id/loser_city_id, gigs.city_id with an explicit is_remote flag instead of free-text "Remote").

erDiagram
  cities ||--o{ dancers : "home city"
  cities ||--o{ profiles : "located in"
  cities ||--o{ events : "takes place in"
  cities ||--o{ community_groups : "serves"
  profiles ||--o{ events : "venue_profile_id"
  profiles ||--o{ bookable_spaces : "offers"
  cities {
    uuid id PK
    text google_place_id UK
    text slug UK
    text name
    text local_name
    text country_code
  }

Consequences

• "Munich", "München" and "Мюнхен" become one city in every count, filter and feed; audience geography is a GROUP BY city_id.
• City URLs stay stable (cities.slug keeps the existing slug rule).
• The v3 sync resolves venue localities through the city service instead of a string map (canonicalisation plan step 5).
• Dropping the free-text columns is the only irreversible step and waits for its own approval.

Stories unblocked

RAZ-85 (audience geography), RAZ-64 and RAZ-50 (artists by city), RAZ-47 and RAZ-139 (real per-city numbers), RAZ-127 (discover by city), RAZ-302 (venue filters), RAZ-45 and RAZ-169 (city directories on ids, not strings).