Initial commit: dashdrm-mp4ff plugin

Add a Streamlink plugin (plugin/dashdrm_mp4ff.py) to support DRM-protected MPEG-DASH streams with optional mp4ff-decrypt integration. Include README with usage and installation notes, an interactive helper (gen.py) that reads vault.json and prints Streamlink commands, a vault.json example, pyproject.toml (declares inquirerpy dependency), .python-version, and .gitignore. This provides the plugin, packaging metadata, and tooling needed to run and test DASH-DRM streams locally.

gen.py

@@ -0,0 +1,46 @@
+import json
+from InquirerPy import prompt
+from InquirerPy.base.control import Choice
+
+VAULT_FILE = "vault.json"
+
+def load_vault():
+    try:
+        with open(VAULT_FILE, "r") as f:
+            return json.load(f)["channels"]
+    except FileNotFoundError:
+        return []
+    
+def main():
+    channels = load_vault()
+    
+    if not channels:
+        print("No channels found in vault.json")
+        return
+
+    choices = [
+        Choice(value=channel, name=f"{channel.get('number', '?')} - {channel.get('name', 'Unknown')}") 
+        for channel in channels
+    ]
+
+    questions = [
+        {
+            "type": "list",
+            "name": "channel",
+            "message": "Select a channel to generate the streamlink command for:",
+            "choices": choices,
+        }
+    ]
+
+    result = prompt(questions)
+    selected_channel = result.get("channel")
+
+    if selected_channel:
+        mpd_url = selected_channel.get("mpd_url", "")
+        keys_list = selected_channel.get("keys", [])
+        keys_str = ",".join(keys_list)
+        command = f'streamlink -l debug --plugin-dirs "./plugin" --dashdrm-mp4ff-use-mp4ff --dashdrm-mp4ff-decryption-key "{keys_str}" "dashdrm://{mpd_url}" best'
+        print(command)
+
+if __name__ == "__main__":
+    main()