Add utility for initializing RCR boundary conditions

utilities/initialize_rcr_boundary_conditions/README.md

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+# Update: Taeouk Kim 2026.08.11
+# RCR Initial Pressure Utility
+
+This utility calculates a phase-aware initial capacitor pressure for RCR boundary conditions and updates the `Initial_pressure` values of all RCR outlets in an svMultiPhysics `solver.xml` file.
+
+## Requirements
+
+- Python 3
+- NumPy
+- One svMultiPhysics `solver.xml` file
+- One inflow waveform file with the `.flow` extension
+
+## Usage
+
+Place `solver.xml` and one `.flow` file in the simulation directory, then run:
+
+```bash
+python /path/to/calculate_rcr_initial_pressure.py
+```
+
+The `.flow` file is detected automatically when exactly one is present. A specific file can also be selected:
+
+```bash
+python /path/to/calculate_rcr_initial_pressure.py --flow inflow.flow
+```
+
+To calculate the pressure without modifying `solver.xml`, use:
+
+```bash
+python /path/to/calculate_rcr_initial_pressure.py --dry-run
+```
+
+## Output
+
+By default, the utility:
+
+- creates `solver.xml.before_rcr_pc_update.bak`;
+- updates `solver.xml` in place; and
+- writes `rcr_initial_pressure_summary.csv`.
+
+Run the following command for all available options:
+
+```bash
+python /path/to/calculate_rcr_initial_pressure.py --help
+```