docs: update README and add help-chat, deduplication docs

README.md:
- Add DAST, pentesting, code graph, AI chat, MCP, help chat to features table
- Add Gitea to tracker list, multi-language LLM triage note
- Update architecture diagram with all 5 workspace crates
- Add new API endpoints (graph, DAST, chat, help, pentest)
- Update dashboard pages table (remove Settings, add 6 new pages)
- Update project structure with new directories
- Add Keycloak, Chromium to external services

New docs:
- docs/features/help-chat.md — Help chat assistant usage, API, config
- docs/features/deduplication.md — Finding dedup across SAST, DAST, PR, issues

Updated:
- docs/features/overview.md — Add help chat section, update tracker list

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

docs/features/overview.md

@@ -1,8 +1,6 @@
 # Dashboard Overview
 
-The Overview page is the landing page of Certifai. It gives you a high-level view of your security posture across all tracked repositories.
-
-![Dashboard overview with stats cards, severity distribution, AI chat, and MCP servers](/screenshots/dashboard-overview.png)
+The Overview page is the landing page of the Compliance Scanner. It gives you a high-level view of your security posture across all tracked repositories.
 
 ## Stats Cards
 
@@ -34,6 +32,10 @@ The overview includes quick-access cards for the AI Chat feature. Each card repr
 
 If you have MCP servers registered, they appear on the overview page with their status and connection details. This lets you quickly check that your MCP integrations are running. See [MCP Integration](/features/mcp-server) for details.
 
+## Help Chat Assistant
+
+A floating help chat button is available in the bottom-right corner of every page. Click it to ask questions about the Compliance Scanner -- how to configure repositories, understand findings, set up webhooks, or use any feature. The assistant is grounded in the project documentation and uses LiteLLM for responses.
+
 ## Recent Scan Runs
 
 The bottom section lists the most recent scan runs across all repositories, showing: