Make registration and signin view configurable via environment variables

Changed DISABLE_REGISTRATION and REQUIRE_SIGNIN_VIEW from hardcoded values to environment variables with sensible defaults (false), allowing deployment-specific configuration without code changes.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

docker-compose.yml

@@ -19,8 +19,8 @@ services:
       - GITEA__server__DOMAIN=${GITEA_DOMAIN}
       - GITEA__server__SSH_DOMAIN=${GITEA_SSH_DOMAIN}
       - GITEA__server__ROOT_URL=${GITEA_ROOT_URL}
-      - GITEA__service__DISABLE_REGISTRATION=true
-      - GITEA__service__REQUIRE_SIGNIN_VIEW=true
+      - GITEA__service__DISABLE_REGISTRATION=${DISABLE_REGISTRATION:-false}
+      - GITEA__service__REQUIRE_SIGNIN_VIEW=${REQUIRE_SIGNIN_VIEW:-false}
       - GITEA__log__MODE=console,file
       - GITEA__log__LEVEL=Info
       - GITEA__log__ROOT_PATH=/data/gitea/log
@@ -57,7 +57,8 @@ services:
     networks:
       - gitea
     healthcheck:
-      test: ["CMD-SHELL", "pg_isready -U ${POSTGRES_USER} -d ${POSTGRES_DATABASE}"]
+      test:
+        ["CMD-SHELL", "pg_isready -U ${POSTGRES_USER} -d ${POSTGRES_DATABASE}"]
       interval: 10s
       timeout: 5s
       retries: 5