feat: show KB overview summary on welcome page in both CLI and web UI

Loads the KB meta overview (generated during ingestion) and displays it
when the chatbot starts, so users immediately see what is in their
knowledge base.

- CLI: KB summary shown in the welcome panel (truncated to ~600 chars)
- Web: KB summary shown in an expandable section before the first message

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app_cli.py

@@ -9,6 +9,7 @@ from rich.text import Text
 
 from src.config_loader import load_config, get_api_key
 from src.ingest import ingest_documents
+from src.kb_meta import load_kb_meta
 from src.query_engine import understand_query
 from src.retriever import retrieve
 from src.verifier import verify_and_respond
@@ -213,6 +214,20 @@ def main() -> None:
         welcome.append("OFF", style="bold red")
         welcome.append(". Use /websearch on to enable.\n\n")
 
+    # KB overview summary
+    kb_overview = load_kb_meta(cfg)
+    if kb_overview:
+        welcome.append("Knowledge Base Contents:\n", style="bold")
+        # Strip the === markers and show the body
+        overview_body = kb_overview
+        for marker in ("=== KNOWLEDGE BASE OVERVIEW ===", "=== END OVERVIEW ==="):
+            overview_body = overview_body.replace(marker, "")
+        overview_body = overview_body.strip()
+        # Truncate for the welcome panel (keep first ~600 chars)
+        if len(overview_body) > 600:
+            overview_body = overview_body[:600].rsplit("\n", 1)[0] + "\n..."
+        welcome.append(overview_body + "\n\n", style="dim")
+
     welcome.append("Type your question, or /help for commands.\n", style="italic")
     welcome.append("Type /quit to exit.", style="italic dim")
     console.print(Panel(welcome, title="Welcome", border_style="cyan"))

app_web.py

@@ -4,6 +4,7 @@ import streamlit as st
 
 from src.config_loader import load_config, get_api_key
 from src.ingest import get_chroma_collection, ingest_documents
+from src.kb_meta import load_kb_meta
 from src.query_engine import understand_query
 from src.retriever import retrieve
 from src.verifier import verify_and_respond
@@ -288,6 +289,17 @@ def main():
 
     st.title(bot_name)
 
+    # Show KB overview on first visit (no messages yet)
+    if not st.session_state.messages:
+        kb_overview = load_kb_meta(cfg)
+        if kb_overview:
+            overview_body = kb_overview
+            for marker in ("=== KNOWLEDGE BASE OVERVIEW ===", "=== END OVERVIEW ==="):
+                overview_body = overview_body.replace(marker, "")
+            overview_body = overview_body.strip()
+            with st.expander("Knowledge Base Contents", expanded=True):
+                st.markdown(overview_body)
+
     render_sidebar()
     render_chat()