test: cover wrong JSON types in the MCP robustness layer

[lukiod]

The robustness layer varies argument values thoroughly (oversized, injection, negative, ReDoS) but always sends the expected type. These nine send a value of the wrong JSON type for the envelope fields parsed before tool dispatch: name, arguments, params, method.

All nine pass against the current binary. This is a regression guard for a class the layer does not currently reach, not a bug report — I went looking for a NULL deref and did not find one; cbm_mcp_parse_request rejects a non-string method before use, and heap_strdup returns NULL safely.

Kept to the envelope. I also wrote per-tool field cases (wrong-typed name_pattern, query, limit) and dropped them: they stop at project validation like the existing adversarial cases, so they added runtime without reaching new code.

Layer goes 23/23 in 88s to 32/32 in 120s on this machine.

[github-actions]

Thanks for opening this — it has been seen, and it is queued.

This note is automated, but it is not a brush-off: it exists so you know where your PR stands instead of having to guess from silence.

Current review status: working through a backlog. 0.9.1-rc.1 is out, so the release freeze that held reviews is over — but it left a large queue of open pull requests behind it, and we are reading through them oldest-first. The background is in discussion #1144.

What that means for this PR, concretely:

• It will not be closed for inactivity. No stale bot touches pull requests here.
• It may still sit a while before a human reads it. That is on us, not on you.
• Older PRs are read first, so a recent one is not being skipped — it is behind a queue.

Things that will genuinely speed it up whenever review does happen:

• Keep it rebased on main — the tree is moving quickly right now, and a conflicting branch cannot be reviewed as the diff you intended.
• Get CI green, or say which failures you believe are pre-existing.
• Keep the change to one claim. Bundled features and refactors get split before they get merged, which costs you a round trip.
• Every commit needs a sign-off (git commit -s) — CI enforces DCO.

If this fixes a bug, a reproduction we can run is worth more than a description of the symptom.

Thanks for contributing, and sorry in advance for the wait.

[DeusData]

Thank you for the focused wrong-type robustness coverage. I have routed this as security-hardening test work for the immediate train with normal priority. The community review queue is currently full, so a complete maintainer review may take a little time, but the contribution is recorded and queued.