feat(ci): add nightly MSDO toolchain breach monitor

.github/aw/actions-lock.json

@@ -5,6 +5,11 @@
       "version": "v8",
       "sha": "ed597411d8f924073f98dfc5c65a23a2325f34cd"
     },
+    "github/gh-aw-actions/setup@v0.61.0": {
+      "repo": "github/gh-aw-actions/setup",
+      "version": "v0.61.0",
+      "sha": "df014dd7d03b638e860b2aeca95c833fd97c8cf1"
+    },
     "github/gh-aw/actions/setup@v0.43.23": {
       "repo": "github/gh-aw/actions/setup",
       "version": "v0.43.23",

.github/toolchain-inventory.yml

@@ -0,0 +1,52 @@
+# MSDO Toolchain Inventory
+# Source of truth for tools monitored by the breach monitor workflow
+# Derived from src/msdo-helpers.ts Tools enum
+#
+# All versions are noted as "latest (runtime-resolved)" because the MSDO CLI
+# resolves tool versions dynamically via NuGet at runtime.
+
+tools:
+  - name: bandit
+    description: Python security linter (finds common security issues in Python code)
+    ecosystem: pypi
+    version: latest (runtime-resolved)
+
+  - name: binskim
+    description: Binary static analysis tool for Windows/Linux binaries
+    ecosystem: nuget
+    version: latest (runtime-resolved)
+
+  - name: checkov
+    description: Infrastructure-as-code security scanner
+    ecosystem: pypi
+    version: latest (runtime-resolved)
+
+  - name: container-mapping
+    description: Container image mapping and inventory
+    ecosystem: nuget
+    version: latest (runtime-resolved)
+
+  - name: eslint
+    description: JavaScript/TypeScript linter with security rules
+    ecosystem: npm
+    version: latest (runtime-resolved)
+
+  - name: templateanalyzer
+    description: ARM/Bicep template security analyzer
+    ecosystem: nuget
+    version: latest (runtime-resolved)
+
+  - name: terrascan
+    description: Terraform/IaC security scanner
+    ecosystem: github
+    version: latest (runtime-resolved)
+
+  - name: trivy
+    description: Comprehensive vulnerability scanner (containers, filesystems, repos)
+    ecosystem: github
+    version: latest (runtime-resolved)
+
+  - name: antimalware
+    description: Windows antimalware scanner (Windows runners only)
+    platform: windows-only
+    version: latest (runtime-resolved)