Wire 0113 malformed merge-arm + managed-collision fixtures

[chris-colinsky]

Summary

PR 6e of the v0.17.0 fixture-wiring series. Implements proposal 0113's general merge-arm malformed handling and wires the managed-collision conformance fixtures behind it.

The shared apply_managed_extras merge arm now gates on well-formedness: a merge-managed extra (llm stop) merges only when it is a string or a list of strings. A malformed value is treated as absent (all-or-nothing, no salvage, no raise), matching spec 0113 and the retrieval embedding_types arm's existing fallback. Previously any value was coerced into the list, so a malformed stop could reach the wire.

Changes

• _managed_extras.py: well-formedness gate on the merge arm; the merge base now resolves via managed_values like the reject arm.
• Un-defer parse for 072/074/075/076 and parse+run for 081; correct the deferral reasons for 073/077/078/079/080 (real streaming / Anthropic / Gemini shape blockers, not the invariants model).
• Model the per-case invariants block (dict[str, bool]) on the llm-provider expected type.
• conformance.toml: 0113 partial to implemented.
• CHANGELOG entry.

Held

075 (llm) and 052 (retrieval) same-name declared collisions stay run-deferred: the reject is unreachable via the real caller path. Parked for the batched spec review, along with an empty-string element edge where the Cohere embedding_types gate is stricter than 0113's structural-only rule.

Testing

Full suite: 1974 passed, 500 skipped. ruff + pyright clean. Pre-merge adversarial review run; findings addressed.

[Copilot]

Pull request overview

Implements spec proposal 0113’s “malformed merge-arm extras are treated as absent” behavior in the shared managed-extras resolver, and unblocks the related managed-collision conformance fixtures by modeling the per-case invariants block and updating fixture deferrals/status.

Changes:

• Update apply_managed_extras merge arm to merge only well-formed stop extras (string or list of strings), otherwise treat the extras value as absent (all-or-nothing, no raise).
• Add unit tests covering malformed/empty-edge merge behavior for stop.
• Wire fixture parsing and conformance bookkeeping for the managed-collision/0113 cases (expected-type model, deferral notes, proposal status, changelog).

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/openarmature/_managed_extras.py	Gates merge-managed extras on well-formedness and resolves merge base consistently with the reject arm.
tests/unit/test_managed_extras.py	Adds focused unit coverage for malformed and edge-case merge inputs (stop).
tests/conformance/harness/expectations.py	Models expected.invariants as dict[str, bool] for managed-collision fixtures.
tests/conformance/test_fixture_parsing.py	Updates deferral inventory to reflect invariants now being parsed and clarifies remaining deferral causes.
tests/conformance/test_llm_provider.py	Removes now-obsolete deferral entry for the 0113 malformed-stop fixture and updates held-collision messaging.
tests/conformance/test_retrieval_provider.py	Updates held-collision deferral messaging for fixture 052 to reflect current rationale.
conformance.toml	Marks proposal 0113 as implemented and updates the implementation note accordingly.
CHANGELOG.md	Adds a release note describing the new malformed-merge behavior and its impact.