TTS: configurable auth, Health check, Phoenix options; .env.example; Gitea CI workflow

Co-authored-by: Cursor <cursoragent@cursor.com>

.gitea/workflows/ci.yml

@@ -0,0 +1,23 @@
+# Gitea Actions: build and test virtual-banker backend on push
+name: CI
+on:
+  push:
+    branches: [master, main]
+  pull_request:
+    branches: [master, main]
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Set up Go
+        uses: actions/setup-go@v5
+        with:
+          go-version: '1.21'
+      - name: Build
+        run: go build ./...
+        working-directory: backend
+      - name: Test
+        run: go test ./...
+        working-directory: backend