feat(scenarios,environments): add markdown description field

- add optional description to scenario and environment entities
- expose description in create/update DTOs, MCP tools, and export DTOs
- render description as markdown on detail pages
- add description editor (CodeEditor) to create/edit forms for both resources

client/src/i18n/locales/en.json

@@ -36,6 +36,7 @@
     "updated": "Environment updated",
     "col_id": "ID",
     "col_name": "Name",
+    "col_description": "Description",
     "col_data": "Data",
     "col_updated": "Updated",
     "empty": "No environments yet.",
@@ -56,10 +57,13 @@
     "form_name": "Name",
     "form_name_placeholder": "e.g. staging, production",
     "form_name_required": "Name is required",
+    "form_description": "Description",
+    "form_description_placeholder": "Describe this environment",
     "form_data": "Data (JSON)",
     "form_data_invalid_json": "Must be a valid JSON object",
     "back": "Environments",
     "field_id": "ID",
+    "field_description": "Description",
     "field_created": "Created",
     "field_updated": "Updated",
     "section_data": "Data"
@@ -115,12 +119,14 @@
     "field_updated": "Updated",
     "field_lastUsed": "Last Used"
   },
-  "scenarios": {    "title": "Scenarios",
+  "scenarios": {
+    "title": "Scenarios",
     "created": "Scenario created",
     "updated": "Scenario updated",
     "run_started": "Scenario run started",
     "col_id": "ID",
     "col_name": "Name",
+    "col_description": "Description",
     "col_updated": "Updated",
     "empty": "No scenarios yet.",
     "loading": "Loading…",
@@ -128,6 +134,7 @@
     "action_delete": "Delete",
     "field_id": "ID",
     "field_name": "Name",
+    "field_description": "Description",
     "field_steps": "Steps",
     "field_created": "Created",
     "field_updated": "Updated",
@@ -148,6 +155,8 @@
     "action_cancel": "Cancel",
     "create_title": "New Scenario",
     "edit_title": "Edit Scenario",
+    "form_description": "Description",
+    "form_description_placeholder": "Describe this scenario",
     "form_name": "Name",
     "form_name_placeholder": "e.g. Login flow",
     "form_name_required": "Name is required",