Sync documentation to current codebase state (v0.2.2)

[Codex-Crusader]

Summary

• README: fixed repo URLs, updated dependency versions, added missing files to project structure
• CONTRIBUTING: fixed badge/clone URLs, updated test count
• CHANGELOG: added v0.2.2 entry covering test expansion, dashboard improvements, security audit
• ROADMAP: updated version + test badges, marked repo restructure as done, closed issue Add signal score legend to README and dashboard #12
• code_flow.md: fixed MAX_WORKERS value and with_market_ctx flag in Diagram 2
• variable_list.md: added price_cache param, error return key, fixed run_scan entry dict structure

Test plan

• All links in README resolve correctly
• Mermaid diagrams in code_flow.md render without errors