docs: rename OSSCodeIQ → Code IQ, rewrite README as user guide with Mermaid diagrams

README.md:
- Rename OSSCodeIQ → Code IQ throughout
- Replace ASCII architecture diagrams with Mermaid flowcharts
- Condense to user guide: remove internal API endpoint listing,
  MCP tool listing, full node/edge type enumerations, duplicate
  tech stack table, memory profile table
- Add compact framework table, server overview table
- Add Mermaid graph model visualization

CLAUDE.md:
- Rename OSSCodeIQ → Code IQ in header and description

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

Author: aksOps

CLAUDE.md

@@ -1,8 +1,8 @@
-# OSSCodeIQ (Java) -- Project Instructions
+# Code IQ (Java) -- Project Instructions
 
 ## What This Project Is
 
-**OSSCodeIQ** -- a CLI tool + server that scans codebases to build a deterministic code knowledge graph. No AI, no external APIs -- pure static analysis. 97 detectors, 35+ languages, Neo4j Embedded graph database, Spring AI MCP server, REST API, web UI.
+**Code IQ** -- a CLI tool + server that scans codebases to build a deterministic code knowledge graph. No AI, no external APIs -- pure static analysis. 97 detectors, 35+ languages, Neo4j Embedded graph database, Spring AI MCP server, REST API, web UI.
 
 - **Maven coordinates:** `io.github.randomcodespace.iq:code-iq`
 - **CLI command:** `code-iq` (via `java -jar`)