fix(api): surface server error messages instead of a bare ✖ HTTP 400

[akoso]

What

Every non-2xx from the MNA API currently renders as a bare ✖ HTTP 400 — that blindness cost a full diagnostic round when variants add was broken. This makes the CLI print whatever the server actually said, defensively.

One implementation, in the openapi-fetch response middleware (src/api/client.ts), so every command benefits — no per-command patching. On a non-2xx the body is read once and a detail is derived in order:

1. message — string, or a string array (NestJS validation convention) joined with ;
2. error
3. a raw non-JSON body, only if it is short (≤ 200 chars) and printable
4. nothing

With a detail: ✖ HTTP 400 — location.coordinates must be { lat, lng }.
Without one: ✖ HTTP 400 — byte-for-byte today's output.

Degradation

Bodies with nothing usable in them fall back to the bare status line: today's production {statusCode, timestamp, path}, an empty body, a body stripped by a proxy, an HTML error page, and the intentionally bare 500. No undefined ever reaches the terminal.

--json

Unchanged and verified end-to-end against a stub server: errors go to stderr via reportAndExit, stdout stays completely empty on failure. Machine output stays machine output.

Tests

src/api/client.test.ts gains cases for message-as-string, message-as-array, error fallback, short non-JSON body, long/unprintable non-JSON body, empty body (reproduces today's exact output), message-less {statusCode, timestamp, path} body, and a bare 500.

Release gating

Version bumped to 0.3.1, but not tagged and not published. The release waits until travel-plans #127 — the server-side fix that stops the global exception filter from dropping HttpException payloads — is merged and deployed, so the improvement is real when it ships.

OpenAPI snapshot: deferred

#127 also adds flat address/latitude/longitude to the v1 event location DTO. Checked the live spec at https://api.mynextadventure.cloud/v1/openapi.json while preparing this: EventLocationV1Dto still has only googlePlaceId/name/formattedAddress/coordinates, and the live spec is otherwise byte-identical to the committed openapi.json. Snapshot left alone; a follow-up commit refreshes it and re-runs bun run codegen after the deploy.

Gates

bun run codegen, bun run typecheck (no diagnostics), bun run lint, bun test (160 pass / 0 fail), bun run build — all clean.

🤖 Generated with Claude Code

https://claude.ai/code/session_01AsdP2hvt4XQhYxkdNREXUq