feat: rename Docker Watcher to Tinyforge

Rebrand the project as Tinyforge to reflect its evolution from a Docker
container watcher into a self-hosted mini CI/deployment platform.

Rename covers: Go module path, Docker labels, DB/config filenames,
JWT issuer, Dockerfile binary, docker-compose, CI workflows, frontend
i18n, README with static sites docs, and all code comments.

scripts/dev-server.sh

@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-# Start (or restart) the Docker Watcher dev server on port 8090.
+# Start (or restart) the Tinyforge dev server on port 8090.
 # Usage: ./scripts/dev-server.sh
 
 set -euo pipefail
@@ -32,6 +32,6 @@ export ENCRYPTION_KEY
 export ADMIN_PASSWORD="${ADMIN_PASSWORD:-admin123}"
 export LISTEN_ADDR="${PORT}"
 
-echo "Starting Docker Watcher on http://localhost:${PORT_NUM}"
+echo "Starting Tinyforge on http://localhost:${PORT_NUM}"
 echo "Login: admin / ${ADMIN_PASSWORD}"
 exec go run ./cmd/server