docs: Status contract drifts between README, DEVELOPER_GUIDE, CLAUDE.md

[Widthdom]

Summary

CLAUDE.md "Status Contract" lists 11 trust fields and asserts that README.md and DEVELOPER_GUIDE.md stay in sync. In practice README.md mentions only a subset, DEVELOPER_GUIDE.md mentions a slightly different subset, and nothing enforces the sync claim. Drift will continue silently until someone notices.

Evidence

• CLAUDE.md "Status Contract" section — enumerates: fold_ready, fold_ready_reason, graph_table_available, issues_table_available, sql_graph_contract_ready, sql_graph_contract_degraded_reason, hotspot_family_ready, hotspot_family_degraded_reason, csharp_symbol_name_ready, csharp_metadata_target_ready, plus degraded_reason/recommended_action/alternative_action in the fold-only path.
• README.md — mention of status --json and which fields are documented.
• DEVELOPER_GUIDE.md — same.

Impact

• New contributors reading any single doc get an incomplete picture of the status JSON contract.
• The "keep these three docs in sync" claim is informal — there is no test or CI lint that enforces it.

Proposed direction

Pick one:

1. Lint-style enforcement: Add a small test that loads the field list from one canonical source (e.g. a JSON schema or a static C# struct) and asserts that all three docs mention each field name. The test fails when a field is added without doc updates.
2. Single source: Reduce the duplicated lists to one canonical doc, and have the other two link to it.
3. At minimum: Bring README.md and DEVELOPER_GUIDE.md back in sync with CLAUDE.md and add a comment to each saying "if you change this list, update the other two".

Repro env

• Branch: main @ 2ee912d (release v1.21.0)

[Widthdom]

Work started on branch fix-issue1452.