fix: align drainage frontend configuration

AGENTS.md

@@ -16,10 +16,12 @@ drainage-network WebGIS. Runtime TypeScript lives under `src/`.
 - `src/mocks/`: MSW handlers and fixtures.
 - `tests/browser/`: product-specific Playwright regressions.
 - `public/`: static drainage and SCADA assets plus the runtime-config placeholder.
+- `server/`: same-origin Edge TTS adapter used by Vite and the production container.
 
-Do not add Next.js APIs or route handlers. Backend and BFF behavior belongs in
-the Agent service or another service. Browser-safe GeoServer reads may happen
-directly when CORS is enabled.
+Do not add Next.js APIs or general BFF routes. Agent behavior belongs in the
+Agent service; the local `server/` exception is limited to the same-origin Edge
+TTS network adapter. Browser-safe GeoServer reads may happen directly when CORS
+is enabled.
 
 ## Commands
 
@@ -81,9 +83,8 @@ runtime configuration, or map interactions. Name tests after behavior.
 ## Configuration and Security
 
 Browser configuration is injected through `/runtime-config.js` and validated in
-`src/shared/config/env.ts`. Use `DRAINAGE_*` variables. Legacy
-`NEXT_PUBLIC_*` values are accepted by the Vite development adapter only to ease
-local migration.
+`src/shared/config/env.ts`. Use `DRAINAGE_*` variables; legacy `NEXT_PUBLIC_*`
+names are not supported.
 
 Do not commit secrets, `.env.local`, generated `dist/`, dependency folders,
 Playwright artifacts, tokens, or session dumps. Keep server-only proxy targets