feat(stack): add gated progressive exposure runtime adapter

CHANGELOG.md

@@ -7,6 +7,13 @@ Tracking starts with the community-docs baseline for this repository.
 
 ## [Unreleased]
 
+### Added
+
+- Add the default-off progressive tool-exposure adapter with five published
+  contracts for exact plan/snapshot materialization, invocation authorization,
+  and content-addressed receipts. The stack surface admits and observes
+  bounded disclosure but never executes or proxies an owner tool.
+
 ### Fixed
 
 - Bind MCP 2.1.1 protocol-lab and KAG receipts to the actually imported SDK

docs/testing/test_inventory.json

@@ -175,6 +175,7 @@
         "mcp/services/abyss-stack-mcp/tests/test_admission_revision.py",
         "mcp/services/abyss-stack-mcp/tests/test_canary.py",
         "mcp/services/abyss-stack-mcp/tests/test_effect.py",
+        "mcp/services/abyss-stack-mcp/tests/test_exposure.py",
         "mcp/services/abyss-stack-mcp/tests/test_observation_producer.py",
         "mcp/services/abyss-stack-mcp/tests/test_overlay.py",
     "mcp/services/abyss-stack-mcp/tests/test_orchestration_host.py",