feat(posture): add deterministic feedback proposals

Assistant: codex
Assistant-Model: gpt-5.6-sol
Assistant-Session: 01a02929-244b-7391-b933-c04010e8eedb

examples/posture-feedback/README.md

@@ -0,0 +1,16 @@
+# Posture Feedback Example
+
+`expired-e2.yaml` is deliberately valid as a posture declaration while carrying
+expired E2 evidence at the example evaluation time. It also has posture and
+zone reviews due within 14 days, an E3 control awaiting evidence, and one
+declared retention gap.
+
+The evaluator reports these as proposals and performs no mutation:
+
+```bash
+uv run tools/posture-feedback/posture_feedback.py \
+  --as-of 2026-08-23T12:00:00Z \
+  --horizon-days 14 \
+  --fail-on none \
+  examples/posture-feedback/expired-e2.yaml
+```