fix(bruno): convert drifted body keys to body.data — CLI scenario runs now carry bodies

Follow-up to the sweep route audit, correcting its diagnosis: the CLI
DOES read .yml bodies — via OpenCollection's `body.data` string form
(the NewDevDBSetup script always worked because it used it). The
failing scenario POSTs used `body.json` (structured) / `body.jsonBody`
(string) — keys the CLI silently ignores, sending Content-Length: 0
with form-urlencoded content-type, so every server bind failed.

- 81 bodies converted to data-form (json maps serialized; jsonBody
  strings kept verbatim, {{vars}} intact).
- 6 pre-existing TRUNCATED payloads repaired: the original generator
  cut bodies at the first {{var}} (every SHA-256-identified scenario
  plus Sync Progress/Sync Bookmarks shipped mid-JSON and 400'd from
  day one). Rewritten whole, faithful to each file's documented
  purpose; book_sha256/book_uuid added to the environment.
- environments: opds_base_url correction from the sweep retained.

Verified live against the rebuilt dev container: the full koreader
scenario tree runs green through `bru run` — 14/14 (202s across
immediate/checkpoint/SHA-256 progress, 200s bookmarks, highlights,
notes; SHA-256 book identification exercised against a real
file_sha256).

bruno/environments/Bookhoard.yml

@@ -40,3 +40,7 @@ variables:
     name: comic_library_id
   - secret: true
     name: manga_library_id
+  - secret: true
+    name: book_sha256
+  - secret: true
+    name: book_uuid