more audit work

src/Tools/__Tests/FixtureUpdater.Tests/AGENTS.md

@@ -0,0 +1,21 @@
+# FixtureUpdater Tests Charter
+
+## Mission
+Validate fixture updater determinism and error handling for Concelier fixture refresh tooling.
+
+## Responsibilities
+- Maintain unit tests for FixtureUpdaterRunner and CLI behaviors.
+- Keep fixtures deterministic and offline-friendly.
+- Track sprint tasks in `TASKS.md` and update the sprint tracker.
+
+## Key Paths
+- `FixtureUpdaterRunnerTests.cs`
+
+## Required Reading
+- `docs/modules/concelier/architecture.md`
+- `docs/implplan/permament/SPRINT_20251229_049_BE_csproj_audit_maint_tests.md`
+
+## Working Agreement
+- 1. Keep tests deterministic (fixed time and IDs, no network).
+- 2. Avoid writing outside temp test directories.
+- 3. Update `TASKS.md` and sprint statuses when work changes.