Implement safe cracking logic and setup development environment

- Added a new `main.cpp` file with logic to parse dial rotations from a file and execute safe cracking based on the parsed data.
- Introduced a `DialRotation` struct to represent the direction and distance of dial rotations.
- Implemented `parseRotations` function to read and parse input from a specified file, returning a vector of `DialRotation` or an error message.
- Created `executeSafeCrack` function to process the dial rotations and print the current state of the dial.
- Added `.clang-format` and `.clang-tidy` configuration files for code formatting and linting.
- Set up a Dockerfile for a development container with necessary tools and dependencies.
- Configured VS Code settings and tasks for building, formatting, and running clang-tidy.
- Added a script to run clang-tidy on the source files, ensuring code quality.

.devcontainer/Dockerfile

@@ -0,0 +1,23 @@
+FROM xianpengshen/clang-tools:21
+
+# Install development tools (cmake, ninja, build essentials)
+USER root
+RUN apt-get update \
+   && apt-get install -y --no-install-recommends \
+   cmake \
+   ninja-build \
+   build-essential \
+   git \
+   python3 \
+   python3-pip \
+   ca-certificates \
+   && rm -rf /var/lib/apt/lists/*
+
+# Create workspace folder (VS Code devcontainer convention)
+ARG WORKSPACE_FOLDER=/workspaces/aoc25
+RUN mkdir -p ${WORKSPACE_FOLDER} && chown -R root:root ${WORKSPACE_FOLDER}
+WORKDIR ${WORKSPACE_FOLDER}
+
+ENV SHELL=/bin/bash
+
+CMD ["bash"]

.devcontainer/devcontainer.json

@@ -0,0 +1,20 @@
+{
+  "name": "aoc25-clang21",
+  "build": {
+    "dockerfile": "Dockerfile"
+  },
+  "workspaceFolder": "/workspaces/aoc25",
+  "workspaceMount": "source=${localWorkspaceFolder},target=/workspaces/aoc25,type=bind,consistency=cached",
+  "settings": {
+    "C_Cpp.default.compilerPath": "/usr/bin/clang++-21",
+    "C_Cpp.default.intelliSenseMode": "linux-clang-x64",
+    "clang-format.executable": "/usr/bin/clang-format-21"
+  },
+  "extensions": [
+    "ms-vscode.cpptools",
+    "ms-vscode.cmake-tools",
+    "llvm-vs-code-extensions.vscode-clangd",
+    "xaver.clang-format"
+  ],
+  "postCreateCommand": "cmake -S . -B build || true"
+}