Add initial implementation of Python helpers and CLI tools

- Create .gitignore to exclude build artifacts
- Add README.md with project description and installation instructions
- Implement pyproject.toml for package metadata and script entry points
- Add console output helpers for command-line scripts
- Implement environment file loading functionality
- Add JSON file I/O helpers
- Create token decoder CLI for decoding JWT claims
- Implement serve-markdown CLI for serving Markdown files as HTML

python_helpers/console.py

@@ -0,0 +1,47 @@
+"""Colored console output helpers for command-line scripts."""
+
+import sys
+
+if sys.stdout.isatty():
+    COLOR_RESET = "\033[0m"
+    COLOR_RED = "\033[0;31m"
+    COLOR_GREEN = "\033[0;32m"
+    COLOR_YELLOW = "\033[0;33m"
+    COLOR_BLUE = "\033[0;34m"
+    COLOR_CYAN = "\033[0;36m"
+else:
+    COLOR_RESET = COLOR_RED = COLOR_GREEN = COLOR_YELLOW = COLOR_BLUE = COLOR_CYAN = ""
+
+
+def fail(message):
+    """Print an error message to stderr and exit with status 1.
+
+    Args:
+        message: error text to print.
+    """
+    print(f"{COLOR_RED}Error: {message}{COLOR_RESET}", file=sys.stderr)
+    sys.exit(1)
+
+
+def print_banner(title, title_color=COLOR_CYAN):
+    """Print a cyan banner line, the given title, and another banner line.
+
+    Args:
+        title: text to print between the banner lines.
+        title_color: color to print the title in; the banner lines themselves are always
+            cyan. Defaults to cyan, matching most banners; pass COLOR_GREEN for a
+            "Setup/Cleanup Complete!" style closing banner.
+    """
+    print(f"{COLOR_CYAN}=========================================={COLOR_RESET}")
+    print(f"{title_color}{title}{COLOR_RESET}")
+    print(f"{COLOR_CYAN}=========================================={COLOR_RESET}")
+
+
+def print_summary_counts(pairs):
+    """Print a flat "Label: count" line for each given (label, count) pair.
+
+    Args:
+        pairs: iterable of (label, count) tuples.
+    """
+    for label, count in pairs:
+        print(f"{label}: {count}")