Initial Aurora Core 0.1 implementation

Production-grade media metadata backend per docs/aurora-core-spec.md:
Aurora-owned UUIDv7 identity system, normalized movie/TV/people/credits
schema, provider abstraction with a TMDb adapter, an idempotent async
ingestion pipeline (normalize -> match -> upsert -> provenance), a
Postgres FTS/trigram search layer, a stateless FastAPI v1 API with
Redis caching/rate-limiting, arq workers, dev/prod Docker Compose
topologies, unit + integration + load tests, CI, and architecture/
database/API/ERD documentation.

Co-Authored-By: Claude Sonnet 5 <[email protected]>

docs/erd.md

@@ -0,0 +1,201 @@
+# Aurora Core — Entity-Relationship Diagram
+
+This is the Core 0.1 schema (36 tables, see [database.md](database.md) for
+column-level detail). Association/junction tables are drawn as relationships
+directly where Mermaid supports it; a few many-to-many tables with their own
+attributes (`movie_companies.role`, `credits.*`) are drawn as entities.
+
+```mermaid
+erDiagram
+    MOVIE ||--o{ MOVIE_ALTERNATE_TITLE : has
+    MOVIE ||--o{ MOVIE_SPOKEN_LANGUAGE : has
+    MOVIE ||--o{ MOVIE_PRODUCTION_COUNTRY : has
+    MOVIE ||--o{ RELEASE_DATE : has
+    MOVIE ||--o{ MOVIE_RECOMMENDATION : recommends
+    MOVIE }o--o{ GENRE : "movie_genres"
+    MOVIE }o--o{ KEYWORD : "movie_keywords"
+    MOVIE }o--o{ COMPANY : "movie_companies"
+    MOVIE }o--|| COLLECTION : "belongs to"
+    MOVIE ||--o{ CREDIT : "cast/crew"
+    MOVIE ||--o{ ARTWORK : "images"
+    MOVIE ||--o{ VIDEO : "trailers"
+    MOVIE ||--o{ EXTERNAL_ID : "provider refs"
+
+    SERIES ||--o{ SEASON : has
+    SEASON ||--o{ EPISODE : has
+    SERIES ||--o{ SERIES_ALTERNATE_TITLE : has
+    SERIES ||--o{ SERIES_SPOKEN_LANGUAGE : has
+    SERIES ||--o{ SERIES_PRODUCTION_COUNTRY : has
+    SERIES }o--o{ GENRE : "series_genres"
+    SERIES }o--o{ KEYWORD : "series_keywords"
+    SERIES }o--o{ COMPANY : "series_companies (network/studio)"
+    SERIES ||--o{ CREDIT : "cast/crew/creators"
+    SERIES ||--o{ ARTWORK : "images"
+    SERIES ||--o{ VIDEO : "trailers"
+    SERIES ||--o{ EXTERNAL_ID : "provider refs"
+    EPISODE ||--o{ CREDIT : "cast/guest stars/crew"
+    EPISODE ||--o{ ARTWORK : "stills"
+    EPISODE ||--o{ EXTERNAL_ID : "provider refs"
+    SEASON ||--o{ ARTWORK : "posters"
+    SEASON ||--o{ EXTERNAL_ID : "provider refs"
+
+    COLLECTION ||--o{ MOVIE : "collection_movies"
+    COLLECTION ||--o{ SERIES : "collection_series"
+    COLLECTION ||--o{ COLLECTION : "collection_relations"
+    COLLECTION ||--o{ ARTWORK : "images"
+
+    COMPANY ||--o{ COMPANY : "parent_company"
+    COMPANY ||--o{ ARTWORK : "logos"
+    COMPANY ||--o{ EXTERNAL_ID : "provider refs"
+    COMPANY }o--o| COUNTRY : "based in"
+
+    PERSON ||--o{ CREDIT : "credited on"
+    PERSON ||--o{ ARTWORK : "profile images"
+    PERSON ||--o{ EXTERNAL_ID : "provider refs"
+
+    PROVIDER ||--o{ PROVIDER_RECORD : "provenance"
+    PROVIDER ||--o{ INGESTION_JOB : "runs"
+    PROVIDER ||--o{ EXTERNAL_ID : "issues"
+    PROVIDER ||--o{ ARTWORK : "sourced"
+    PROVIDER ||--o{ VIDEO : "sourced"
+    PROVIDER ||--o{ CREDIT : "sourced"
+    INGESTION_JOB ||--o{ PROVIDER_RECORD : produces
+
+    COUNTRY ||--o{ CERTIFICATION : defines
+    RELEASE_DATE }o--o| CERTIFICATION : rated
+
+    MOVIE {
+        uuid id PK
+        string title
+        string sort_title
+        enum status
+        date primary_release_date
+        int runtime_minutes
+        uuid collection_id FK
+        uuid source_provider_id FK
+    }
+    SERIES {
+        uuid id PK
+        string title
+        enum status
+        date first_air_date
+        int number_of_seasons
+    }
+    SEASON {
+        uuid id PK
+        uuid series_id FK
+        int season_number
+    }
+    EPISODE {
+        uuid id PK
+        uuid season_id FK
+        uuid series_id FK
+        int episode_number
+    }
+    PERSON {
+        uuid id PK
+        string name
+        date birthday
+        string known_for_department
+    }
+    CREDIT {
+        uuid id PK
+        uuid person_id FK
+        string entity_type
+        uuid entity_id
+        string department
+        string job
+        string character
+    }
+    COMPANY {
+        uuid id PK
+        string name
+        enum company_type
+        uuid parent_company_id FK
+    }
+    COLLECTION {
+        uuid id PK
+        string name
+        string slug
+    }
+    GENRE {
+        uuid id PK
+        string name
+    }
+    KEYWORD {
+        uuid id PK
+        string name
+    }
+    ARTWORK {
+        uuid id PK
+        string entity_type
+        uuid entity_id
+        enum artwork_type
+        uuid provider_id FK
+        string original_url
+    }
+    VIDEO {
+        uuid id PK
+        string entity_type
+        uuid entity_id
+        enum video_type
+        uuid provider_id FK
+        string url
+    }
+    EXTERNAL_ID {
+        uuid id PK
+        string entity_type
+        uuid entity_id
+        uuid provider_id FK
+        string external_id
+    }
+    PROVIDER {
+        uuid id PK
+        string slug
+        string name
+    }
+    PROVIDER_RECORD {
+        uuid id PK
+        uuid provider_id FK
+        string entity_type
+        string external_id
+        uuid aurora_entity_id
+        enum match_confidence
+        jsonb raw_data
+    }
+    INGESTION_JOB {
+        uuid id PK
+        uuid provider_id FK
+        string job_type
+        enum status
+        string idempotency_key
+    }
+    COUNTRY {
+        string code PK
+        string name
+    }
+    CERTIFICATION {
+        uuid id PK
+        string country_code FK
+        string system
+        string rating
+    }
+    RELEASE_DATE {
+        uuid id PK
+        uuid entity_id
+        string country_code FK
+        date release_date
+        uuid certification_id FK
+    }
+```
+
+## Notes on the polymorphic tables
+
+`CREDIT`, `ARTWORK`, `VIDEO`, `EXTERNAL_ID`, and `RELEASE_DATE` attach to more
+than one entity type (movie, series, season, episode, person, company,
+collection) via an `(entity_type, entity_id)` pair rather than a typed
+foreign key. Postgres can't enforce referential integrity across a
+polymorphic pair with a single `FOREIGN KEY`, so integrity there is enforced
+by the repository/service layer (`app/repositories/polymorphic.py`), not the
+schema. See [database.md](database.md#polymorphic-associations) for the
+tradeoff.