test: expect the MCP view of BM answers

- viaMCP, includeBody and the material views (no body unless asked)
- jz.bm.mcp-links: absolute url / *_url under MCP only
- jz.bm.manage keyed per user for dispatched calls
- bm_material and bm_materials in the pinned tool list
Compile-only stubs; the tests fail on their assertions.

controllers/api/mcp_view.go

@@ -0,0 +1,20 @@
+package api
+
+import (
+	"net/http"
+)
+
+// viaMCP reports whether r is an MCP tool call.
+func viaMCP(r *http.Request) bool { return false }
+
+// includeBody reports whether r asks for the material body.
+func includeBody(r *http.Request) bool { return false }
+
+// materialView is the answer of GET /materials/{id} for r.
+func materialView(r *http.Request, d materialDetailJSON) any { return d }
+
+// managedMaterialView is a managed material for r.
+func managedMaterialView(r *http.Request, m managedMaterialJSON, write bool) any { return m }
+
+// managedMaterialDetailView is a managed material with its files for r.
+func managedMaterialDetailView(r *http.Request, d managedMaterialDetailJSON, write bool) any { return d }