feat(web): add password protection for web console

- Add `web_password` config to enable login authentication
- Use stateless HMAC-signed token (survives restart, invalidates on password change)
- Add `web_session_expire_days` config (default 30 days)
- Protect all API endpoints with auth check (401 on failure)
- Add login page UI with auto-redirect on session expiry
- Add password management in config page (masked display, inline edit)
- Add tooltip hints for Agent config fields
- Update default agent_max_context_turns to 20, agent_max_steps to 20
- Update docs and docker-compose.yml

docs/en/knowledge/index.mdx

@@ -42,6 +42,10 @@ Knowledge writing is an autonomous Agent behavior, triggered in these scenarios:
 
 Each knowledge page includes cross-reference links to related pages, gradually building a knowledge graph.
 
+<Frame>
+  <img src="https://gist.github.com/user-attachments/assets/3ce92f78-1863-4820-8fa8-660c0f2b7f09" alt="Conversational knowledge ingest" />
+</Frame>
+
 ## Knowledge Retrieval
 
 The Agent can retrieve knowledge during conversation through:
@@ -55,9 +59,17 @@ The Agent can retrieve knowledge during conversation through:
 The web console provides a dedicated "Knowledge" module with:
 
 - **Document browsing** — Tree-style directory structure, searchable and collapsible, click to view content
-- **Knowledge graph** — D3.js force-directed graph visualizing relationships between knowledge pages
+- **Knowledge graph** — Interactive graph visualizing relationships between knowledge pages
 - **Chat integration** — Knowledge document links referenced in Agent replies are clickable for direct navigation
 
+<Frame>
+  <img src="https://gist.github.com/user-attachments/assets/b7b9d6be-0ac1-4c65-803b-2c6b36bd59a7" alt="Knowledge document browsing" />
+</Frame>
+
+<Frame>
+  <img src="https://gist.github.com/user-attachments/assets/44ae68ca-96cc-40b9-ab33-cdbec34c2379" alt="Knowledge graph visualization" />
+</Frame>
+
 ## CLI Commands
 
 Manage the knowledge base with the `/knowledge` command: