fix(deploy): seed .env.example into APP_DIR if missing

The Start Docker stack step does `cd $APP_DIR && [ -f .env ] || cp .env.example .env`
but never ensured .env.example existed in APP_DIR. The rsync in the Deploy step
also doesn't copy it. The first deploy on a fresh host therefore failed with
'cp: cannot stat .env.example' before ever bringing up the stack.

Fix: copy .env.example from the workspace into APP_DIR if it isn't already
there, before the cd.

.gitea/workflows/deploy.yml

@@ -28,6 +28,8 @@ jobs:
         run: |
           APP_DIR=/home/tyler/route-commerce
           mkdir -p $APP_DIR
+          # Seed .env.example into APP_DIR if missing (it lives in the repo, not in APP_DIR)
+          [ -f $APP_DIR/.env.example ] || cp .env.example $APP_DIR/.env.example
           cd $APP_DIR
           [ -f .env ] || cp .env.example .env
           # Append production secrets to .env (overriding .env.example defaults)