Implement rp CLI: rich-print markdown, JSON, code, and more

- Add typer CLI with auto file-type detection by extension
- Support markdown (rich.Markdown), JSON (rich.JSON), and 30+ code
  languages via Pygments syntax highlighting
- Features: line numbers toggle, pager support, stdin input,
  configurable color themes
- Project metadata: MIT license, author, classifiers, entry point

src/rp/detect.py

@@ -0,0 +1,83 @@
+"""File type detection for rp."""
+
+from __future__ import annotations
+
+import json
+from pathlib import Path
+
+EXTENSION_MAP: dict[str, str] = {
+    ".md": "markdown",
+    ".json": "json",
+    ".py": "python",
+    ".pyw": "python",
+    ".js": "javascript",
+    ".mjs": "javascript",
+    ".ts": "typescript",
+    ".tsx": "typescript",
+    ".jsx": "jsx",
+    ".css": "css",
+    ".scss": "scss",
+    ".html": "html",
+    ".htm": "html",
+    ".xml": "xml",
+    ".yaml": "yaml",
+    ".yml": "yaml",
+    ".toml": "toml",
+    ".sh": "bash",
+    ".bash": "bash",
+    ".zsh": "bash",
+    ".sql": "sql",
+    ".rs": "rust",
+    ".go": "go",
+    ".java": "java",
+    ".c": "c",
+    ".h": "c",
+    ".cpp": "cpp",
+    ".hpp": "cpp",
+    ".cc": "cpp",
+    ".rb": "ruby",
+    ".php": "php",
+    ".swift": "swift",
+    ".kt": "kotlin",
+    ".r": "r",
+    ".R": "r",
+    ".lua": "lua",
+    ".dockerfile": "docker",
+    ".ini": "ini",
+    ".cfg": "ini",
+    ".diff": "diff",
+    ".patch": "diff",
+    ".tex": "latex",
+}
+
+_FILENAME_MAP: dict[str, str] = {
+    "Dockerfile": "docker",
+    "Makefile": "make",
+}
+
+
+def detect_type(
+    path: str | None = None,
+    content: str | None = None,
+    explicit_type: str | None = None,
+) -> str:
+    if explicit_type is not None:
+        return explicit_type
+
+    if path is not None:
+        p = Path(path)
+        name = p.name
+        if name in _FILENAME_MAP:
+            return _FILENAME_MAP[name]
+        suffix = p.suffix.lower()
+        if suffix in EXTENSION_MAP:
+            return EXTENSION_MAP[suffix]
+
+    if content is not None:
+        try:
+            json.loads(content[:1000])
+            return "json"
+        except (json.JSONDecodeError, ValueError):
+            pass
+
+    return "text"