refactor(presi): replace NestJS backend with lightweight Hono server

The Presi NestJS backend (40 source files, 50 deps) was a CRUD wrapper
around decks, slides, and themes — all now handled by local-first sync.

Only the share-link feature requires server-side state (public URLs
without auth), so a minimal Hono + Bun server replaces the entire
NestJS backend:

- apps/presi/apps/server/ — Hono server with share routes + GDPR admin
  Uses @manacore/shared-hono for auth (JWKS), health, admin, errors
- Web app API client stripped to share-only (was 270 lines → 90 lines)
- Removed from docker-compose, CI/CD, Prometheus, env generation
- NestJS backend deleted (40 TS files, 8 test specs, 3038 lines)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

scripts/generate-env.mjs

@@ -270,20 +270,7 @@ const APP_CONFIGS = [
 		},
 	},
 
-	// Presi Backend (NestJS)
-	{
-		path: 'apps/presi/apps/backend/.env',
-		vars: {
-			NODE_ENV: () => 'development',
-			PORT: (env) => env.PRESI_BACKEND_PORT || '3008',
-			DATABASE_URL: (env) => env.PRESI_DATABASE_URL,
-			MANA_CORE_AUTH_URL: (env) => env.MANA_CORE_AUTH_URL,
-			DEV_BYPASS_AUTH: () => 'true',
-			DEV_USER_ID: (env) => env.DEV_USER_ID || '00000000-0000-0000-0000-000000000000',
-			JWT_PUBLIC_KEY: (env) => env.JWT_PUBLIC_KEY,
-			CORS_ORIGINS: (env) => env.CORS_ORIGINS,
-		},
-	},
+	// Presi Backend: REMOVED — replaced by Hono server (apps/presi/apps/server)
 
 	// Presi Web (SvelteKit)
 	{