feat: generic template generation — any WebDAV template usable without code

Add GenericTemplateGenerator that downloads templates from WebDAV,
fills entity placeholders automatically (case/contact/account), and
supports custom placeholders from AI conversation. New API endpoint
generateFromTemplate exposed for the AI Gateway.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

manifest.json

@@ -3,7 +3,7 @@
     "module": "SmartAssistant",
     "description": "Unified AI Assistant for Legal CRM — floating chat with case memory, office alerts, and AI Gateway integration",
     "author": "klear",
-    "version": "2.6.1",
+    "version": "2.7.0",
     "acceptableVersions": [
         ">=8.0.0"
     ],