Display contribution evidence and queue context on FC pages

Acceptance tracker for contribution evidence and queue context on FC pages. **#5388 now delivers publication and display together**, incorporating former #5389. #4394 owns the PR/dependency map; #5376 owns contribution and publication acceptance.

## Implementation

- [x] Shared validated evidence reader checks index, manifest and artifact bindings.
- [x] Problem-page renderer shows outcomes, producer attribution, historical/current/unconfirmed applicability and explicit unavailable-feed states.
- [x] CLI handoff and related-PR context use exact repository/module/file/revision joins; no fuzzy equivalence or automatic duplicate closure.
- [x] Board migration [Open Formal Workflows #2](https://github.com/williamjblair/open-formal-workflows/pull/2) merged on 10 September 2026 as `fdfe5beabb334a9738ee09c963c461ca2b2a031e`. Queue timing and historical evidence identifiers remain preserved. No replacement board PR is needed.
- [x] Malformed optional work entries now become an explicit invalid-feed state instead of aborting site generation. The consolidated branch retains the fix and shell-safe CLI handoffs that explicitly select the page catalog. 22 browser-script tests pass.

## Deployment and handoff acceptance

- [ ] #5375's complete native `conjectures.json` and provenance descriptor are deployed at the production endpoint. Confirm actual statement text, source links, variants and matching snapshot integrity.
- [x] Fork feeds are configured to the existing evidence branch and deployed Open Formal Workflows `work.json`. Upstream configuration still requires maintainer acceptance; no new catalog or evidence service was created.
- [x] Fork browser checks: Green 72 statements, hovers, exact source links, passing/incomplete historical operator reports and copied CLI command; Erdős 92 variants; Erdős 427 conditional proof. An isolated website-only preview preserved catalog/manifest bytes and remained usable without optional feeds. Deterministic reader tests cover rejected/errored/invalid feed states. The upstream queue is explicitly unavailable for fork joins.
- [x] Fork publication history: after changing disposable PR #10, CLI and website show the report as historical with its original passing outcome. The board retains the report but its upstream queue cannot establish fork PR applicability.
- [ ] Repeat the complete board/site handoff against the accepted production catalog and owning repository publisher.
- [ ] A reader outside this conversation can identify the statement, sources, evidence producer, applicability, maintainer status and concrete next action.
- [x] [Board deployment 34582305572](https://github.com/williamjblair/open-formal-workflows/actions/runs/34582305572) passed against its compatible shared-reader pin. No repin was required. Its queue covers upstream FC; it cannot establish applicability for a disposable fork PR.

The [final fork deployment](https://github.com/williamjblair/formal-conjectures/actions/runs/34594294249) passed at `eee8f2ec741ac7772ba075fd8023e5716beb78c6`. [Qualification record](https://github.com/williamjblair/formal-conjectures/blob/e4dd405fc6803eb744922b3e527917e2cbd619d1/toolkit/qualification/rc3-final.md) retains the exact published digest, browser observations and preview check. The site has 5,264 declarations in one 3,105,385-byte catalog. These are operator checks; independent reader and upstream production acceptance remain open.

#5389 stays closed because its code is consolidated into #5388, not because website work was cancelled. Close this issue only after the deployment and reader-handoff gates pass.

**Layout qualification passed:** [final fork deployment](https://github.com/williamjblair/formal-conjectures/actions/runs/34594294249) at `eee8f2ec7`. Fresh desktop and 390 px browser-emulated mobile pages contain native statements and CLI commands within their scroll areas. The deployed stylesheet matches the qualified source.

Start with the consolidated work in #5388 and the remaining deployment gates in this issue. Verify conjectures.json, its provenance descriptor, the deployed work.json, and the qualification record at toolkit/qualification/rc3-final.md; done means the accepted production catalog and owning publisher pass the complete board/site handoff and an independent reader can identify evidence, applicability, maintainer status, and the next action.

Written by the indexing model from the issue text.