feat(fault-injection): Add fault injection API service

- FastAPI service for remote fault injection
- Endpoints for GPU XID injection, network faults
- Dockerfile for containerized deployment
- Requirements with FastAPI, kubernetes client

Provides HTTP API for triggering fault injection from tests.

tests/fault_tolerance/hardware/fault-injection-service/api-service/Dockerfile

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+# SPDX-FileCopyrightText: Copyright (c) 2025 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+#
+# SPDX-License-Identifier: Apache-2.0
+
+FROM python:3.12-slim
+
+WORKDIR /app
+
+# Install system dependencies
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    curl \
+    && rm -rf /var/lib/apt/lists/*
+
+# Copy requirements and install Python dependencies
+COPY requirements.txt .
+RUN pip install --no-cache-dir -r requirements.txt
+
+# Copy application code
+COPY main.py .
+
+# Health check
+HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 \
+    CMD curl -f http://localhost:8080/health || exit 1
+
+# Run as non-root user
+RUN useradd -m -u 1000 faultinjection && chown -R faultinjection:faultinjection /app
+USER faultinjection
+
+EXPOSE 8080
+
+CMD ["python", "main.py"]
+