doc updates

docs/mcp_layout.md

@@ -29,8 +29,10 @@ treeView-beta
       "docs"
          "index.md"
          "architecture.md"
+         "content.md"
+         "frontmatter.md"
          "mcp_layout.md"
-         "mcp_contract_steps_1_5.md"
+         "uris.md"
          "skills"
             "new-skill"
                "SKILL.md"
@@ -153,8 +155,6 @@ When clients cannot attach MCP resources directly, thin catalog tools may retrie
 
 ## URI Compatibility Policy
 
-This phase is a greenfield break-and-replace baseline.
-
 1. Canonical URIs are the only supported URIs in this runtime.
 2. No backward-compatibility aliases or dual registration paths are maintained.
 3. Contract changes should update clients to canonical URIs directly.