DUNGEONS-30: add access gateway with Telegram and Discord approvals

Co-authored-by: multica-agent <github@multica.ai>

.env.example

@@ -0,0 +1,42 @@
+# The private Dungeons-Ground origin. Keep it inaccessible from the public internet.
+UPSTREAM_URL=http://127.0.0.1:3000
+# The public gateway origin; HTTPS is required with NODE_ENV=production.
+PUBLIC_URL=http://localhost:8080
+HOST=0.0.0.0
+PORT=8080
+NODE_ENV=development
+# Generate with: node -e "console.log(require('crypto').randomBytes(32).toString('hex'))"
+SESSION_SECRET=replace-with-a-random-secret-at-least-32-characters
+DATA_FILE=./data/access.json
+
+CODE_LENGTH=10
+CODE_TTL_DAYS=15
+SESSION_TTL_HOURS=360
+REQUEST_TTL_HOURS=24
+REQUEST_COOLDOWN_SECONDS=300
+LOGIN_ATTEMPTS=5
+LOGIN_WINDOW_SECONDS=900
+GLOBAL_LOGIN_ATTEMPTS=100
+# Set only when the proxy is reachable exclusively through your trusted edge.
+# The edge must OVERWRITE X-Forwarded-For with the single client IP.
+TRUST_PROXY=false
+
+# Either or both bots can be enabled. Empty tokens disable a provider.
+# Telegram uses long polling. Users and admins must first /start the bot in DM.
+TELEGRAM_BOT_TOKEN=
+TELEGRAM_BOT_USERNAME=
+TELEGRAM_ADMIN_IDS=
+
+# Discord uses a signed HTTP interactions endpoint at /_access/discord.
+DISCORD_BOT_TOKEN=
+DISCORD_APPLICATION_ID=
+DISCORD_PUBLIC_KEY=
+DISCORD_ADMIN_IDS=
+# Channel/server link where users can invoke /access (shown on the gate).
+DISCORD_ACCESS_URL=
+# Optional: register /access immediately in one server instead of globally.
+DISCORD_GUILD_ID=
+
+# Comma-separated request details sent to admins. platform, user_id and request_id
+# are always included. Names/handles are informational, never authorization IDs.
+ADMIN_REQUEST_FIELDS=username,display_name,language_code,guild_id,created_at