Initial commit: establish deterministic rod-string solver stack.

Set up the C solver core, Node API orchestration, TS GUI workflow, and engineering documentation with cleaned repo hygiene for private Git hosting.

Made-with: Cursor

docs/engineering/case-schema.md

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+# Case schema and import contract
+
+Owner: Rods Project Team  
+Status: Active  
+Last Updated: 2026-04-16  
+Version: 0.2.0
+
+## Canonical input
+
+- Root: `INPRoot/Case`  
+- Example: `data/cases/base-case.xml`
+
+## Parsed fields used by solver (SI after `xmlParser`)
+
+### Core (required)
+
+- `PumpingSpeed` — SPM  
+- `PumpDepth` — MD to pump (case units → m)  
+- `MeasuredDepthArray`, `InclinationFromVerticalArray` — trajectory (`:` separated)  
+- `AzimuthFromNorthArray` — optional for vertical; required for full 3D curvature in API validation  
+
+### Friction / contact
+
+- `RodFrictionCoefficient` — Coulomb \(\mu\) baseline  
+- `StuffingBoxFriction`, `PumpFriction` — case force units → N  
+- `MoldedGuideFrictionRatio`, `WheeledGuideFrictionRatio`, `OtherGuideFrictionRatio` — scale effective \(\mu\) along string (`heuristic` blend)  
+
+### Rod string / materials
+
+- `TaperDiameterArray`, `TaperLengthArray`, `TaperModulusArray`, `TaperWeightArray`, `TaperMTSArray`  
+- `RodTypeArray` — maps to steel vs fiberglass density/modulus defaults when modulus not set  
+- `TubingAnchorLocation`  
+- `SinkerBarDiameter`, `SinkerBarLength`  
+- `RodGuideTypeArray`, `RodGuideWeightArray` — metadata / future contact  
+
+### Damping
+
+- `UpStrokeDampingFactor`, `DownStrokeDampingFactor`  
+- `NonDimensionalFluidDamping` — Gibbs-style dimensionless damping input  
+
+### Pump / fluid (valve + buoyancy helpers)
+
+- `PumpDiameter`, `PumpIntakePressure`, `PumpFillageOption`, `PercentPumpFillage`  
+- `WaterCut`, `WaterSpecGravity`, `FluidLevelOilGravity`, `TubingGradient`, `TubingSize`  
+- `PercentageUpstrokeTime`, `PercentageDownstrokeTime`  
+- `PumpingUnitID`, `PumpingSpeedOption` — metadata for future kinematics  
+
+### Units
+
+- `UnitsSelection` — drives internal conversion (see `units.md`)  
+
+## Unknown / unsupported field policy
+
+- Parse immediate `Case` children into `rawFields`.  
+- Fields outside the MVP subset used for **solver** remain in `unsupportedFields` but are **preserved** in API responses.  
+- Do not silently drop imported tags.
+
+## Validation rules
+
+- Required for parse: `PumpingSpeed`, `PumpDepth`, `MeasuredDepthArray`, `InclinationFromVerticalArray`.  
+- Trajectory arrays must have equal lengths after parse.  
+- Numeric parse failures throw explicit errors.