feat(docs): add CLI subcommands documentation and file naming strategies

- Introduced new documentation for CLI subcommands: `upload` and `watch`, detailing their usage, flags, and examples.
- Added a section on file naming and conflict strategies, explaining how users can customize file names and handle duplicates via `/config` and `/fnametmpl` commands.
- Translated the new documentation into Chinese for broader accessibility.

docs/content/en/usage/cli.md

@@ -0,0 +1,90 @@
+---
+title: "CLI Subcommands"
+weight: 21
+---
+
+# CLI Subcommands
+
+Besides running the Telegram bot with `./saveany-bot` (no subcommand), the binary exposes two helper subcommands for moving local files into a storage backend: `upload` (one-shot) and `watch` (continuous).
+
+These subcommands load the same `config.toml` as the bot, initialize the database and caches, then perform their task. They do **not** start the Telegram bot itself, although storages of type `telegram` will spin up the bot client just for the upload.
+
+## `upload` — Upload a Single File
+
+```
+saveany-bot upload -f <file> -s <storage> [-d <dir>] [--no-progress]
+```
+
+Flags:
+
+| Flag | Required | Description |
+|---|---|---|
+| `-f, --file` | Yes | Path to the local file to upload |
+| `-s, --storage` | Yes | Target storage name (must exist in `config.toml`) |
+| `-d, --dir` | No | Destination directory within the storage. Defaults to the storage's `base_path` |
+| `--no-progress` | No | Disable the terminal progress bar |
+
+Examples:
+
+```bash
+# Upload a file to the default dir of storage "MyAlist"
+./saveany-bot upload -f ./movie.mp4 -s MyAlist
+
+# Upload into a specific subdirectory
+./saveany-bot upload -f ./movie.mp4 -s MyAlist -d movies/2026
+
+# Upload via Telegram storage without a progress bar
+./saveany-bot upload -f ./photo.jpg -s MyChannel --no-progress
+```
+
+## `watch` — Watch a Directory and Auto-Upload
+
+The `watch` subcommand continuously monitors a local directory and uploads created or modified files to a storage backend, preserving the relative directory structure from the watch root.
+
+```
+saveany-bot watch -p <path> -s <storage> [-d <dir>] [options]
+```
+
+Flags:
+
+| Flag | Default | Description |
+|---|---|---|
+| `-p, --path` | *(required)* | Local directory to watch |
+| `-s, --storage` | *(required)* | Target storage name |
+| `-d, --dir` | storage's `base_path` | Destination directory within the storage |
+| `-r, --recursive` | `false` | Watch subdirectories recursively |
+| `--overwrite` | `false` | Overwrite existing files on the storage instead of skipping them |
+| `--initial-scan` | `false` | Upload files already present in the directory on startup |
+| `--debounce` | `2s` | How long to wait after the last write before uploading a file |
+| `--upload-workers` | `config.workers` | Number of concurrent uploads |
+| `--retry-delay` | `3s` | Delay between upload retries |
+
+{{< hint info >}}
+Write-completion detection: the watcher debounces per file and only uploads once the file size stays unchanged across the debounce window, so partial/write-in-progress files are not uploaded.
+<br />
+If a file changes while being uploaded, it is re-uploaded once after the current upload finishes (instead of being queued multiple times).
+{{< /hint >}}
+
+Examples:
+
+```bash
+# Watch ./inbox and upload new files to "MyAlist" recursively
+./saveany-bot watch -p ./inbox -s MyAlist -r
+
+# Watch with a custom destination dir and overwrite
+./saveany-bot watch -p ./inbox -s MyAlist -d backup --overwrite
+
+# On startup, also upload everything already in ./inbox
+./saveany-bot watch -p ./inbox -s MyAlist --initial-scan
+```
+
+### Behavior notes
+
+- Relative directory structure is preserved under the destination directory. A file written to `./inbox/sub/file.txt` with `--path ./inbox` is uploaded to `<dest_dir>/sub/file.txt`.
+- `watch` runs until interrupted (e.g. `Ctrl-C` / `SIGINT`); in-flight uploads are drained before exit.
+- Retries follow the global `retry` value from `config.toml`, with `--retry-delay` between attempts.
+- Telegram-type storages will start the bot client automatically to perform uploads.
+
+{{< hint warning >}}
+`watch` is unrelated to the in-bot `/watch` command (which watches Telegram chats). This subcommand watches a **local filesystem directory** and uploads to a storage backend, independent of Telegram.
+{{< /hint >}}