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.

web/src/lib/i18n/en.json

@@ -1,6 +1,6 @@
 {
   "app": {
-    "name": "Docker Watcher",
+    "name": "Tinyforge",
     "version": "v0.1"
   },
   "health": {
@@ -508,7 +508,7 @@
     "password": "Password"
   },
   "login": {
-    "title": "Docker Watcher",
+    "title": "Tinyforge",
     "subtitle": "Sign in to your account",
     "username": "Username",
     "password": "Password",
@@ -819,7 +819,7 @@
   },
   "dns": {
     "title": "DNS Records",
-    "description": "View and manage DNS records created by Docker Watcher.",
+    "description": "View and manage DNS records created by Tinyforge.",
     "wildcardActive": "Wildcard DNS Mode Active",
     "wildcardActiveDesc": "DNS records are managed externally via wildcard DNS. Disable wildcard DNS in Settings to manage records individually.",
     "refresh": "Refresh",