Proxy API routes through the vite dev server to keep local dev same-origin (#23779)

Replaces #23774 (closed), rebased on latest main.

## Problem

Since the cookie-session migration (#23642), the front sends every
request with `credentials: 'include'` and the server only reflects
`Access-Control-Allow-Origin` for the exact origins in the credentialed
allowlist (`SERVER_URL`, `FRONTEND_URL`, `AUTH_COOKIE_ALLOWED_ORIGINS`).
Any other origin gets the `*` wildcard, which browsers reject for
credentialed requests.

Local dev is split-origin by default (front on `localhost:3001`, API on
`localhost:3000`), and with `IS_MULTIWORKSPACE_ENABLED` every workspace
subdomain (`apple.localhost:3001`, ...) is yet another origin. Each
locally created workspace would need a manual
`AUTH_COOKIE_ALLOWED_ORIGINS` entry.

## Solution

Make local dev same-origin instead of widening the CORS policy: the vite
dev server now proxies all top-level API route prefixes to the backend,
and the front calls its own origin.

- `vite.config.ts` adds a `server.proxy` covering the backend's
top-level prefixes (`/graphql`, `/metadata`, `/admin-panel`, `/auth`,
`/rest`, `/file`, `/client-config`, ...), defined in
`src/config/apiProxyPrefixes.ts`. Keys are anchored regexes
(`^/auth($|[/?])`) so SPA routes sharing a prefix (`/authorize`,
`/settings`) are not swallowed. The target defaults to
`http://localhost:3000` and follows `REACT_APP_SERVER_BASE_URL`.
`changeOrigin` stays off so the backend sees the browser's Host:
same-origin checks (CSRF, cookie issuance) and workspace resolution by
subdomain work unchanged through the proxy.
- `config/index.ts` collapses to
`window._env_?.REACT_APP_SERVER_BASE_URL || window.location.origin`.
Every supported production path injects `window._env_` (docker
entrypoint fails hard without `REACT_APP_SERVER_BASE_URL`; a
server-served front gets it from `generateFrontConfig()`), and in dev
the current origin is correct on `localhost:3001` and every
`*.localhost:3001` workspace subdomain thanks to the proxy. The removed
`http://<hostname>:3000` fallback only served an un-injected production
bundle browsed on localhost, a setup whose credentialed auth the
cookie-session migration had already broken.

The credentialed allowlist itself is unchanged and stays strict; since
dev traffic is same-origin, the per-subdomain cookie-allowlist problem
disappears without loosening any production CORS/CSRF policy.

## Tests

- `src/config/__tests__/apiProxyPrefixes.test.ts` guards the proxy
boundary in both directions: representative backend path shapes
(including `/metadata?query=...` and `/auth/...`) must match, every SPA
route from the `AppPath` enum and vite's own dev paths must not — so a
future route collision fails unit tests instead of breaking dev.
- Verified against running dev servers: API paths proxy to the backend
from both `localhost:3001` and `apple.localhost:3001`, while SPA routes
`/settings` and `/authorize` still serve the vite app; a same-origin
POST from `apple.localhost:3001` goes through with no CORS involvement.
- `lint:diff-with-main` and `typecheck` pass for twenty-front.

---------

Co-authored-by: Félix Malfait <felix@twenty.com>

packages/twenty-server/src/engine/metadata-modules/route-trigger/route-trigger.controller.ts

@@ -12,7 +12,7 @@ import {
 } from '@nestjs/common';
 
 import { Request, Response } from 'express';
-import { HTTPMethod } from 'twenty-shared/types';
+import { ApiPath, HTTPMethod } from 'twenty-shared/types';
 
 import { NoPermissionGuard } from 'src/engine/guards/no-permission.guard';
 import { PublicEndpointGuard } from 'src/engine/guards/public-endpoint.guard';
@@ -20,7 +20,7 @@ import { RouteTriggerRestApiExceptionFilter } from 'src/engine/core-modules/logi
 import { RouteTriggerService } from 'src/engine/core-modules/logic-function/logic-function-trigger/triggers/route/route-trigger.service';
 import { sendRouteTriggerResponse } from 'src/engine/core-modules/logic-function/logic-function-trigger/triggers/route/utils/route-trigger-response.util';
 
-@Controller('s')
+@Controller(ApiPath.RouteTrigger)
 @UseGuards(PublicEndpointGuard, NoPermissionGuard)
 @UseFilters(RouteTriggerRestApiExceptionFilter)
 export class RouteTriggerController {