add comprehensive linting: yamllint, flake8, black, isort, shellcheck, and markdownlint

.yamllint

@@ -0,0 +1,31 @@
+extends: default
+
+rules:
+  # Line length
+  line-length:
+    max: 120
+    level: warning
+  
+  # Document start
+  document-start: disable
+  
+  # Trailing spaces
+  trailing-spaces: enable
+  
+  # Truthy values
+  truthy:
+    check-keys: false
+  
+  # Comments
+  comments:
+    min-spaces-from-content: 1
+  
+  # Indentation
+  indentation:
+    spaces: 2
+    indent-sequences: true
+  
+  # Empty lines
+  empty-lines:
+    max: 1
+    max-end: 1