chore(release): bump v1.18.1 [skip-docs]

Version 1.18.1 in plugin.json, the README badge and SECURITY.md, with the
changelog entry. The README screenshot table notes that the dark
onboarding variant was removed. Not tagged.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -8,7 +8,7 @@ Microsoft AI Solution Architect — structured architecture guidance for the ful
 
 *AI-generated: all code produced by Claude Code through dialog-driven development. Every change is human-directed, reviewed, and validated before commit.*
 
-![Version](https://img.shields.io/badge/version-1.18.0-blue)
+![Version](https://img.shields.io/badge/version-1.18.1-blue)
 ![Platform](https://img.shields.io/badge/platform-Claude_Code_Plugin-purple)
 ![Docs](https://img.shields.io/badge/reference_docs-389-green)
 ![Agents](https://img.shields.io/badge/agents-12-orange)
@@ -443,7 +443,7 @@ Screenshots of every surface in both themes live in `playground/screenshots/v1.1
 
 | # | File | What you see |
 |---|------|--------------|
-| 01 | `01-onboarding-empty-{dark,light}.png` | Onboarding surface, empty state |
+| 01 | `01-onboarding-empty-light.png` | Onboarding surface, empty state (the dark variant was removed in 1.18.1; regenerate to restore it) |
 | 02 | `02-project-rapporter-regulatory-{dark,light}.png` | All 6 regulatory renderers (classify pyramid, requirements, transparency, FRIA, conformity kanban, DPIA matrix) |
 | 03 | `03-project-rapporter-security-{dark,light}.png` | 6×5 + 7×5 risk matrices, radar, top-risks, residual-pair, recommendation-card, review kanban |
 | 03 | `03-project-rapporter-economy-{dark,light}.png` | Cost distribution P10/P50/P90, license capability matrix |