Fix deployment_environment default so the debugger reads UAT

project.godot's API URLs already pointed at UAT (us3q.ranaze.com), but
deployment_environment itself was still "development" - a leftover
label that never matched the actual origin. Since the UAT-only feature
gates (Dynamic Questions, CCS Cases, Flashcards) check for the literal
"uat" value, running from the Godot editor/debugger hid all three even
though it's UAT in every other respect.

Set it to "uat" to match reality, and update the two places that
sed-patch this value at build time (web/Dockerfile for the UAT/PRD web
builds, tools/export_steam_release.sh for the Steam build) so they
still match the source string they're replacing.

project.godot

@@ -64,7 +64,7 @@ textures/vram_compression/import_etc2_astc=true
 
 [step3]
 
-deployment_environment="development"
+deployment_environment="uat"
 questions_api_url="https://us3q.ranaze.com/api/questions/search"
 question_reports_api_url="https://us3q.ranaze.com/api/question-reports"
 app_feedback_api_url="https://us3q.ranaze.com/api/app-feedback"