feat: migrate app to local Fastify and Postgres stack

Replace Supabase auth and search runtime with a local Fastify API, PostgreSQL/PostGIS schema, and local session handling. Scaffold the worker and deep-research foundations while keeping the existing research, dashboard, and map flows running on the new backend.

server/src/config/env.ts

@@ -0,0 +1,26 @@
+import { z } from 'zod';
+
+const envSchema = z.object({
+  NODE_ENV: z.enum(['development', 'test', 'production']).default('development'),
+  APP_HOST: z.string().default('0.0.0.0'),
+  APP_PORT: z.coerce.number().int().positive().default(4000),
+  APP_ORIGIN: z.string().default('http://localhost:3000'),
+  DATABASE_URL: z.string().min(1, 'DATABASE_URL is required'),
+  COOKIE_SECRET: z.string().min(1, 'COOKIE_SECRET is required'),
+  GOOGLE_MAPS_SERVER_KEY: z.string().optional(),
+  PG_BOSS_SCHEMA: z.string().default('pgboss'),
+  SESSION_TTL_DAYS: z.coerce.number().int().positive().default(30),
+});
+
+export type AppEnv = z.infer<typeof envSchema>;
+
+let cachedEnv: AppEnv | null = null;
+
+export function getEnv(): AppEnv {
+  if (cachedEnv) {
+    return cachedEnv;
+  }
+
+  cachedEnv = envSchema.parse(process.env);
+  return cachedEnv;
+}