Restructure Hydrotech Beam project — KB-integrated layout

New project structure with knowledge base integration:
- kb/ with components, materials, fea, dev generations
- models/ for reference NX files (golden copies)
- studies/ for self-contained optimization campaigns
- deliverables/ for final outputs
- DECISIONS.md decision log (6 decisions tracked)
- BREAKDOWN.md (moved from 1_breakdown/)
- Gen 001 created from intake + technical breakdown

KB extension file: atomizer/shared/skills/knowledge-base-atomizer-ext.md

Refs: DEC-HB-004, DEC-HB-005, DEC-HB-006

projects/hydrotech-beam/kb/_index.md

@@ -0,0 +1,47 @@
+# Knowledge Base — Hydrotech Beam
+
+**Project:** Hydrotech Beam Structural Optimization
+**Generation:** 001
+**Last updated:** 2026-02-09
+
+---
+
+## Overview
+
+Sandwich I-beam optimization for a test fixture. Steel construction with lightening holes in the web. Goal: reduce mass from ~974 kg while meeting displacement (≤ 10 mm) and stress (≤ 130 MPa) constraints.
+
+## Components
+
+| Component | File | Status |
+|-----------|------|--------|
+| Sandwich Beam | [sandwich-beam.md](components/sandwich-beam.md) | Initial |
+
+## Materials
+
+| Material | File | Status |
+|----------|------|--------|
+| Steel (AISI) | [steel-aisi.md](materials/steel-aisi.md) | Initial |
+
+## FEA
+
+| Model | File | Status |
+|-------|------|--------|
+| Static Analysis (SOL 101) | [fea/models/sol101-static.md](fea/models/sol101-static.md) | Pending gap resolution |
+
+## Generations
+
+| Gen | Date | Summary |
+|-----|------|---------|
+| 001 | 2026-02-09 | Initial KB from intake + technical breakdown |
+
+## Open Tasks
+
+- ❓ G1: Beam length and support conditions
+- ❓ G2: Loading definition (point? distributed? self-weight?)
+- ❓ G3: Displacement measurement location and DOF
+- ❓ G4: Stress constraint scope (whole model? exclude supports?)
+- ❓ G5: Geometric feasibility of hole patterns at extremes
+- ❓ G6: Result sensors in Beam_sim1.sim
+- ❓ G7: NX parametric rebuild reliability across full range
+- ❓ G8: Mesh type, density, convergence status
+- ❓ G9: 130 MPa stress limit basis (yield? safety factor?)