feat(config): Add AtomizerSpec v2.0 schema and migrate all studies

Added JSON Schema:
- optimization_engine/schemas/atomizer_spec_v2.json

Migrated 28 studies to AtomizerSpec v2.0 format:
- Drone_Gimbal studies (1)
- M1_Mirror studies (21)
- M2_Mirror studies (2)
- SheetMetal_Bracket studies (4)

Each atomizer_spec.json is the unified configuration containing:
- Design variables with bounds and expressions
- Extractors (standard and custom)
- Objectives and constraints
- Optimization algorithm settings
- Canvas layout information

studies/Simple_Bracket/bracket_stiffness_optimization/atomizer_spec.json

@@ -0,0 +1,225 @@
+{
+  "meta": {
+    "version": "2.0",
+    "created": "2026-01-17T15:35:12.041483Z",
+    "modified": "2026-01-17T15:35:12.041483Z",
+    "created_by": "migration",
+    "modified_by": "migration",
+    "study_name": "bracket_stiffness_optimization",
+    "description": "Maximize bracket stiffness while minimizing mass (constraint: mass ≤ 0.2 kg)",
+    "tags": []
+  },
+  "model": {
+    "sim": {
+      "path": "1_setup/model/Bracket_sim1.sim",
+      "solver": "NX_Nastran",
+      "solution_type": "SOL101"
+    },
+    "nx_part": {
+      "path": "1_setup/model/Bracket.prt"
+    },
+    "fem": {
+      "path": "1_setup/model/Bracket_fem1.fem"
+    }
+  },
+  "design_variables": [
+    {
+      "id": "dv_001",
+      "name": "support_angle",
+      "expression_name": "support_angle",
+      "type": "continuous",
+      "bounds": {
+        "min": 20.0,
+        "max": 70.0
+      },
+      "baseline": 60.0,
+      "units": "degrees",
+      "enabled": true,
+      "description": "Angle of support arm relative to base",
+      "canvas_position": {
+        "x": 50,
+        "y": 100
+      }
+    },
+    {
+      "id": "dv_002",
+      "name": "tip_thickness",
+      "expression_name": "tip_thickness",
+      "type": "continuous",
+      "bounds": {
+        "min": 30.0,
+        "max": 60.0
+      },
+      "baseline": 30.0,
+      "units": "mm",
+      "enabled": true,
+      "description": "Thickness of bracket tip where load is applied",
+      "canvas_position": {
+        "x": 50,
+        "y": 180
+      }
+    }
+  ],
+  "extractors": [
+    {
+      "id": "ext_001",
+      "name": "BracketStiffnessExtractor Extractor",
+      "type": "displacement",
+      "builtin": true,
+      "config": {
+        "result_type": "z",
+        "metric": "max_abs"
+      },
+      "outputs": [
+        {
+          "name": "stiffness",
+          "metric": "max_abs"
+        },
+        {
+          "name": "mass",
+          "metric": "max_abs"
+        }
+      ],
+      "canvas_position": {
+        "x": 740,
+        "y": 100
+      }
+    },
+    {
+      "id": "ext_002",
+      "name": "Mass Extractor",
+      "type": "mass",
+      "builtin": true,
+      "outputs": [
+        {
+          "name": "mass_kg",
+          "metric": "total"
+        }
+      ],
+      "canvas_position": {
+        "x": 740,
+        "y": 250
+      }
+    }
+  ],
+  "objectives": [
+    {
+      "id": "obj_001",
+      "name": "Structural stiffness (N/mm) calculated as Force/Displacement",
+      "direction": "maximize",
+      "weight": 1.0,
+      "source": {
+        "extractor_id": "ext_001",
+        "output_name": "stiffness"
+      },
+      "target": null,
+      "units": "",
+      "canvas_position": {
+        "x": 1020,
+        "y": 100
+      }
+    },
+    {
+      "id": "obj_002",
+      "name": "Total mass (kg) - secondary objective with hard constraint",
+      "direction": "minimize",
+      "weight": 0.1,
+      "source": {
+        "extractor_id": "ext_001",
+        "output_name": "mass"
+      },
+      "target": null,
+      "units": "",
+      "canvas_position": {
+        "x": 1020,
+        "y": 200
+      }
+    }
+  ],
+  "constraints": [
+    {
+      "id": "con_001",
+      "name": "Maximum allowable mass: 200 grams",
+      "type": "hard",
+      "operator": "<",
+      "threshold": 0.2,
+      "source": {
+        "extractor_id": "ext_002",
+        "output_name": "mass_kg"
+      },
+      "penalty_config": {
+        "method": "quadratic",
+        "weight": 1000.0
+      },
+      "canvas_position": {
+        "x": 1020,
+        "y": 400
+      }
+    }
+  ],
+  "optimization": {
+    "algorithm": {
+      "type": "NSGA-II",
+      "config": {
+        "population_size": 50,
+        "seed": 42
+      }
+    },
+    "budget": {
+      "max_trials": 50
+    },
+    "canvas_position": {
+      "x": 1300,
+      "y": 150
+    }
+  },
+  "canvas": {
+    "edges": [
+      {
+        "source": "dv_001",
+        "target": "model"
+      },
+      {
+        "source": "dv_002",
+        "target": "model"
+      },
+      {
+        "source": "model",
+        "target": "solver"
+      },
+      {
+        "source": "solver",
+        "target": "ext_001"
+      },
+      {
+        "source": "solver",
+        "target": "ext_002"
+      },
+      {
+        "source": "ext_001",
+        "target": "obj_001"
+      },
+      {
+        "source": "ext_001",
+        "target": "obj_002"
+      },
+      {
+        "source": "ext_002",
+        "target": "con_001"
+      },
+      {
+        "source": "obj_001",
+        "target": "optimization"
+      },
+      {
+        "source": "obj_002",
+        "target": "optimization"
+      },
+      {
+        "source": "con_001",
+        "target": "optimization"
+      }
+    ],
+    "layout_version": "2.0"
+  }
+}