refactor: Add clang-tidy checks and simplify codebase

.clang-tidy

@@ -0,0 +1,30 @@
+Checks: |
+  -*,
+  abseil-*,
+  bugprone-*,
+  clang-analyzer-*,
+  misc-*,
+  modernize-*,
+  performance-*,
+  portability-*,
+  readability-*,
+  llvm-*,
+  -bugprone-easily-swappable-parameters,
+  -readability-avoid-const-params-in-decls,
+  -readability-identifier-length
+
+CheckOptions:
+  - key: readability-inconsistent-declaration-parameter-name.Strict
+    value: true
+  - key: readability-identifier-naming.StructCase
+    value: lower_case
+  - key: readability-identifier-naming.FunctionCase
+    value: lower_case
+  - key: readability-identifier-naming.VariableCase
+    value: lower_case
+  - key: readability-identifier-naming.EnumConstantCase
+    value: UPPER_CASE
+  - key: readability-identifier-naming.MacroDefinitionCase
+    value: UPPER_CASE
+  - key: readability-function-cognitive-complexity.Threshold
+    value: 15