Add a public API wiki at /wiki

Builds docs/ into a static site via mkdocs + mkdocs-material in its own
Docker build stage (docs-builder), so mkdocs itself never ends up in the
runtime image -- only the rendered HTML does, mounted at /wiki alongside
the existing /docs OpenAPI schema (unconditionally, unlike /docs, since
this is curated content meant to be public regardless of
AURORA_API_DOCS_ENABLED).

docs/aurora-core-spec.md (the internal build spec, referenced by "section
N" comments throughout the codebase) is excluded from the built site
entirely via exclude_docs, not just left out of the nav -- it was never
meant for public consumption.

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

docs/api.md

@@ -2,7 +2,8 @@
 
 Base path: `/api/v1`. Interactive OpenAPI docs are available at `/docs` in
 any environment where `AURORA_API_DOCS_ENABLED=true` (default; set to
-`false` to hide docs in production — section 32).
+`false` to hide docs in production — section 32). This same document is
+also published as a browsable page at `/wiki/api/` (see `mkdocs.yml`).
 
 All responses are JSON, built from Pydantic response schemas
 (`app/schemas/`), never from serialized ORM objects (section 18). Errors use

docs/index.md

@@ -0,0 +1,33 @@
+# Aurora Core
+
+Aurora Core is the metadata backend behind [AMDBS](https://www.amdbs.net) — a
+TMDb/IMDb-style canonical data layer for movies, TV, people, and everything
+that connects them.
+
+This wiki documents the public, read-only HTTP API. If you're building
+against Aurora Core, start with the [API Reference](api.md).
+
+## Base URL
+
+```
+https://api.amdbs.net/api/v1
+```
+
+All responses are JSON. Every entity has a stable, type-prefixed id (e.g.
+`aur_movie_01m1q7p1c...`) — always use the id a response gave you rather
+than constructing one yourself.
+
+## Interactive docs
+
+A live, explorable OpenAPI schema (Swagger UI) is available at
+[`/docs`](/docs) alongside this wiki, when enabled in the current
+environment.
+
+## Where to go next
+
+- **[API Reference](api.md)** — every endpoint, grouped by resource, with
+  query parameters and real example responses.
+- **[Architecture](architecture.md)** — how Aurora Core is put together:
+  ingestion pipeline, caching, provider abstraction.
+- **[Database](database.md)** — the schema itself, table by table.
+- **[Entity relationships](erd.md)** — the same schema as a diagram.