Install anipy-cli in Docker image

Install anipy-cli systemwide during the Docker build so fallback downloads work inside the container without extra setup, and update the README to describe the new Docker behavior.

README.md

@@ -28,7 +28,7 @@ Current version: `0.47.0`
 Requirements:
 
 - `ani-cli` installed and available in `PATH`
-- Optional: `anipy-cli` installed and available in `PATH` if you want automatic fallback retries
+- Optional: `anipy-cli` installed and available in `PATH` if you want automatic fallback retries outside Docker
 - Common runtime tools used by `ani-cli`, especially `curl`, `ffmpeg`, `fzf`, `grep`, `openssl`, `sed`, `aria2c`, and `yt-dlp`
 
 Run locally:
@@ -93,6 +93,7 @@ Docker notes:
 - `USER_UID` and `USER_GID` help keep mounted files owned by your host user
 - `UPDATE_ON_START=true` runs `ani-cli --update` before startup
 - `ANI_CLI_WEB_BRANCH` lets the image clone a specific `ani-cli-web` branch at build time
+- `anipy-cli` is installed systemwide inside the container, so fallback retries are available without extra container setup
 
 ## Key behavior
 
@@ -115,7 +116,7 @@ Docker notes:
 
 - Optional and configured from `/config`
 - When enabled, a failed `ani-cli` queue job retries once with `anipy-cli`
-- `anipy-cli` should be installed separately on the host or inside your container if you want the retry path to be available
+- Docker images install `anipy-cli` automatically; non-Docker installs should provide it in `PATH` themselves
 
 ### Jellyfin handoff