test(export): byte-stable golden snapshots over a synthetic state

[2000game]

The fixture is synthetic deliberately: this repo is public, so no live
campus, Bereich or status name belongs in it. The proof that the export
matches a real estate runs in the private config repo, where that state
already lives, as part of the migration gate.

What the fixture does carry is every shape the renderer can trip on —
id 0, a key that is not a valid HCL identifier (!3 Aktiv -> g_3_aktiv),
all five resource types, and every camelCase field that maps to a
snake_case attribute.

---

_{Stack created with GitHub Stacks CLI • Give Feedback 💬}