docs: Add documentation for various features including Aria2, direct download links, parsers, storage rules, silent mode, storage transfer, chat watching, and yt-dlp video download

- Created new markdown files for Aria2 download, direct download links, parsers, storage rules, silent mode, storage transfer, chat watching, and yt-dlp video download.
- Included usage examples, configuration instructions, and detailed explanations for each feature.
- Translated documentation into Chinese for accessibility.

docs/content/en/usage/aria2.md

@@ -0,0 +1,41 @@
+---
+title: "Aria2 Download"
+weight: 6
+---
+
+# Aria2 Download
+
+{{< hint warning >}}
+This feature requires enabling Aria2 in the configuration file and configuring the RPC connection.
+{{< /hint >}}
+
+Use the `/aria2dl` command to download files via the Aria2 download manager, supporting HTTP/HTTPS, FTP, BitTorrent, and other protocols.
+
+```bash
+/aria2dl <uri1> [uri2] [uri3] ...
+```
+
+Examples:
+
+```bash
+# Download HTTP link
+/aria2dl https://example.com/file.zip
+
+# Download magnet link
+/aria2dl magnet:?xt=urn:btih:...
+
+# Download torrent file (need to upload .torrent file first)
+/aria2dl https://example.com/file.torrent
+```
+
+Configure Aria2:
+
+Add to `config.toml`:
+
+```toml
+[aria2]
+enable = true
+url = "http://localhost:6800/jsonrpc"
+secret = "your-rpc-secret"  # If rpc-secret is configured
+remove_after_transfer = true  # Remove local files after transfer
+```