refactor: split main.rs into more files; add docs

.gitignore

@@ -1 +1,25 @@
-/target
+# Generated by Cargo
+# Lockfile should be checked in for binaries, but not for libraries.
+# Cargo.lock
+
+# The cargo build artifacts directory
+/target/
+
+# Local development tool configuration
+.opencode/
+
+# IDE/Editor specific files
+.vscode/
+.idea/
+*.sublime-project
+*.sublime-workspace
+
+# Environment variables
+.env
+
+# Operating System files
+.DS_Store
+Thumbs.db
+
+# Miscellaneous
+*.log