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.

tools/export_steam_release.sh

@@ -24,7 +24,7 @@ cp "${PROJECT_FILE}" "${BACKUP_FILE}"
 
 BUILD_REVISION="$(git -C "${REPO_ROOT}" rev-parse HEAD)"
 sed -i \
-  -e "s|deployment_environment=\"development\"|deployment_environment=\"prd\"|" \
+  -e "s|deployment_environment=\"uat\"|deployment_environment=\"prd\"|" \
   -e "s|build_revision=\"development\"|build_revision=\"${BUILD_REVISION}\"|" \
   -e "s|https://us3q.ranaze.com|https://s3q.ranaze.com|g" \
   "${PROJECT_FILE}"