feat(docs): Add comprehensive documentation for Vexer, Vulnerability Explorer, and Zastava modules

- Introduced AGENTS.md, README.md, TASKS.md, and implementation_plan.md for Vexer, detailing mission, responsibilities, key components, and operational notes.
- Established similar documentation structure for Vulnerability Explorer and Zastava modules, including their respective workflows, integrations, and observability notes.
- Created risk scoring profiles documentation outlining the core workflow, factor model, governance, and deliverables.
- Ensured all modules adhere to the Aggregation-Only Contract and maintain determinism and provenance in outputs.

docs/modules/notify/resources/schemas/notify-template@1.json

@@ -0,0 +1,55 @@
+{
+  "$id": "https://stella-ops.org/schemas/notify/notify-template@1.json",
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "title": "Notify Template",
+  "type": "object",
+  "required": [
+    "schemaVersion",
+    "templateId",
+    "tenantId",
+    "channelType",
+    "key",
+    "locale",
+    "body",
+    "renderMode",
+    "format",
+    "createdAt",
+    "updatedAt"
+  ],
+  "properties": {
+    "schemaVersion": {"type": "string", "const": "notify.template@1"},
+    "templateId": {"type": "string"},
+    "tenantId": {"type": "string"},
+    "channelType": {
+      "type": "string",
+      "enum": ["slack", "teams", "email", "webhook", "custom"]
+    },
+    "key": {"type": "string"},
+    "locale": {"type": "string"},
+    "body": {"type": "string"},
+    "description": {"type": "string"},
+    "renderMode": {
+      "type": "string",
+      "enum": ["markdown", "html", "adaptiveCard", "plainText", "json"]
+    },
+    "format": {
+      "type": "string",
+      "enum": ["slack", "teams", "email", "webhook", "json"]
+    },
+    "metadata": {"$ref": "#/$defs/stringMap"},
+    "createdBy": {"type": "string"},
+    "createdAt": {"type": "string", "format": "date-time"},
+    "updatedBy": {"type": "string"},
+    "updatedAt": {"type": "string", "format": "date-time"}
+  },
+  "additionalProperties": false,
+  "$defs": {
+    "stringMap": {
+      "type": "object",
+      "patternProperties": {
+        ".*": {"type": "string"}
+      },
+      "additionalProperties": false
+    }
+  }
+}