feat: Phase 1 — multi-topic KB foundation

Generalize the Knowledge Base from insurance-only to multi-domain.
Introduces kb_topic table (shira-hermes), topic-aware endpoints
(/kb/topics, /kb/search, /kb/ask, /kb/ask/stream all accept topic_id),
a topic picker <select> in the EspoCRM UI (localStorage-persisted),
and renames the LLM tool search_insurance_kb → search_legal_kb.
All existing sources migrate to topic_id=1 (ביטוח לאומי); the UI
defaults to that topic so no visible regression for current users.

Refs Task Master #12

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

manifest.json

@@ -1,7 +1,7 @@
 {
     "name": "KnowledgeBase",
     "module": "KnowledgeBase",
-    "version": "0.2.1",
+    "version": "0.3.0",
     "acceptableVersions": [
         ">=8.0.0"
     ],