chore: rename module from torrentclaw-cli to unarr

- Rename Go module path github.com/torrentclaw/torrentclaw-cli → github.com/torrentclaw/unarr
- Update all imports, ldflags, scripts, docs, and Docker config
- Add GitHub Actions release workflow (goreleaser on tag push)

docker-build.sh

@@ -1,12 +1,12 @@
 #!/bin/sh
 # Build the unarr Docker image.
-# Must be run from the torrentclaw-cli directory (or its parent).
+# Must be run from the unarr directory (or its parent).
 set -e
 
 SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
 PARENT_DIR="$(dirname "$SCRIPT_DIR")"
 
-# Build from parent dir so both torrentclaw-cli/ and go-client/ are in context
+# Build from parent dir so both unarr/ and go-client/ are in context
 docker build \
     -f "$SCRIPT_DIR/Dockerfile" \
     -t torrentclaw/unarr:latest \