Implements jeaddons CLI tool

Adds a CLI tool to copy files or folders from a git repository into the current project based on a registry.

The tool provides commands to:
- `add`: Copies files/folders based on registry entries.
- `list`: Lists available registry entries.

Registry entries are defined in `jeAddons/registry.py`.
The tool supports overriding the registry's ref and destination.

jeAddons/registry.py

@@ -1,9 +1,37 @@
-import json
-import urllib.request
-
-REGISTRY_URL = "https://raw.githubusercontent.com/acme/registry/main/registry.json"
+from typing import TypedDict
 
 
-def load_registry():
-    with urllib.request.urlopen(REGISTRY_URL) as r:
-        return json.load(r)
+class RegistryEntry(TypedDict, total=False):
+    repo: str
+    path: str
+    ref: str
+    dest: str
+
+
+# Manage your repositories, files, and folders here.
+# Key = addon name you pass to `jeaddons add <name>`.
+REGISTRY: dict[str, RegistryEntry] = {
+    # "button": {
+    #     "repo": "https://github.com/your-org/templates.git",
+    #     "path": "src/components/Button.tsx",
+    #     "ref": "main",
+    #     "dest": "src/components",
+    # },
+    # "ui": {
+    #     "repo": "https://github.com/your-org/templates.git",
+    #     "path": "src/components/ui",
+    #     "ref": "v1.2.0",
+    #     "dest": "src/components",
+    # },
+}
+
+
+def load_registry() -> dict[str, RegistryEntry]:
+    return REGISTRY
+
+
+def get_registry_entry(name: str) -> RegistryEntry:
+    registry = load_registry()
+    if name not in registry:
+        raise KeyError(name)
+    return registry[name]