feat(e2e): #146 MTProto Telegram user client runner

- Add standalone C# console runner tests/e2e/runner/ using WTelegramClient
- Provide TelegramUserClient wrapper: login, create supergroup, invite bot,
  send messages/commands, read recent messages, wait for bot reply
- Add .env.example and runner .gitignore to keep secrets/session files out of git
- Update E2E README with runner instructions and status table
- Runner project intentionally excluded from GM-Relay.slnx to avoid CI/AOT impact

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/e2e/runner/.env.example

@@ -0,0 +1,19 @@
+# Configuration for the GmRelay E2E MTProto runner.
+# Copy this file to .env and fill in real values.
+# NEVER commit .env or *.session files to git.
+
+# Telegram user account credentials (MTProto)
+api_id=12345678
+api_hash=abcdef0123456789abcdef0123456789
+phone_number=+1234567890
+
+# Bot under test
+TELEGRAM_BOT_USERNAME=gmrelay_test_bot
+TELEGRAM_BOT_TOKEN=1234567890:ABCDEF...token
+
+# Web dashboard under test
+GMRELAY_E2E_BASE_URL=http://localhost:8080
+GMRELAY_E2E_TELEGRAM_ID=9000000001
+
+# PostgreSQL connection string (optional, used for seeding/cleanup)
+GMRELAY_E2E_DATABASE_URL=Host=localhost;Database=gmrelay;Username=postgres;Password=postgres