feat: add 4 gated single agents (Rust Refactor, LLM Post-Training, UI Finish-Gate, Data Viz) (#742)

Lands four gated single-agent contributions via a consolidated branch
(avoids the README-conflict cascade of parallel fork PRs). Each passed
the full gate: lint 0/0, originality 0.0%, canonical structure, and a
manual conceptual-dupe check against the existing roster.

- Rust Refactoring Specialist (engineering) — behavior-aware, evidence-based
  Rust refactoring across crates/traits/modules. (#741, @TanasiDesigns)
- LLM Post-Training Engineer (engineering) — SFT/DPO/GRPO/RLVR experiment
  gating, checkpoint integrity, failure classification. Distinct sub-specialty
  from AI Engineer. (#740, @kaining-never-stop)
- UI Finish-Gate Reviewer (design) — anti-generic UI finish gate; catches
  interchangeable UI before ship via evidence + a written design contract.
  Distinct from the testing-division Reality Checker. (#739, @samuelbushi)
- Data Visualization Engineer (engineering) — chart-type selection, perceptually
  honest encodings, colorblind-safe palettes, performant D3/Vega. (#729, @Hotragn)

README roster rows added for all four; Hermes generated count 265 -> 269.
All guards green (divisions/tools/runbooks/hermes-plugin/lint).

Closes #741
Closes #740
Closes #739
Closes #729

Co-authored-by: TanasiDesigns <TanasiDesigns@users.noreply.github.com>
Co-authored-by: kaining-never-stop <kaining-never-stop@users.noreply.github.com>
Co-authored-by: samuelbushi <samuelbushi@users.noreply.github.com>
Co-authored-by: Hotragn <Hotragn@users.noreply.github.com>
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

README.md

@@ -170,6 +170,9 @@ Building the future, one commit at a time.
 | 🔍 [RAG Pipeline Engineer](engineering/engineering-rag-pipeline-engineer.md) | Production RAG pipelines | Chunking, retrieval quality, hybrid search, re-ranking, eval-driven iteration |
 | 🗄️ [GaussDB Expert Engineer](engineering/engineering-gaussdb-expert.md) | Huawei GaussDB OLTP | Enterprise OLTP performance, HA, and migration on Huawei's GaussDB |
 | 🕵️ [Privacy Engineer](engineering/engineering-privacy-engineer.md) | PII discovery, data minimization, consent enforcement, DSAR/deletion pipelines | Implementing privacy in code, right-to-be-forgotten across services, retention automation |
+| 🦀 [Rust Refactoring Specialist](engineering/engineering-rust-refactoring-specialist.md) | Behavior-aware Rust refactoring | Reforming crates/traits/modules with evidence-based, behavior-preserving changes |
+| 🧪 [LLM Post-Training Engineer](engineering/engineering-llm-post-training-engineer.md) | Post-training stack (SFT/DPO/GRPO/RLVR) | Evidence-based experiment gating, checkpoint integrity, failure classification |
+| 📈 [Data Visualization Engineer](engineering/engineering-data-visualization-engineer.md) | Perceptually honest data viz | Chart-type selection, colorblind-safe palettes, performant D3/Vega rendering |
 
 ### 🎨 Design Division
 
@@ -186,6 +189,7 @@ Making it beautiful, usable, and delightful.
 | 📷 [Image Prompt Engineer](design/design-image-prompt-engineer.md) | AI image generation prompts, photography | Photography prompts for Midjourney, DALL-E, Stable Diffusion |
 | 🌈 [Inclusive Visuals Specialist](design/design-inclusive-visuals-specialist.md) | Representation, bias mitigation, authentic imagery | Generating culturally accurate AI images and video |
 | 🎭 [Persona Walkthrough Specialist](design/design-persona-walkthrough.md) | Persona-driven cognitive walkthroughs | Simulating user reactions and friction at each scroll position |
+| 🧱 [UI Finish-Gate Reviewer](design/design-ui-finish-gate-reviewer.md) | Anti-generic UI finish gate | Catching interchangeable UI before ship via evidence + a written design contract |
 
 ### 💰 Paid Media Division