v2.4.0 — internationalization (EN/RU) + custom git templates

- i18n engine (lib/i18n.sh, lib/lang/en.sh, lib/lang/ru.sh)
- first-run language picker, persisted to .language + config.json
- install.sh, common.sh, backup.sh, templates_catalog.sh wired through t()/tf()
- backup.sh preserves .language marker and records language in metadata.json
- custom git template feature (first item in pro template picker)
  * validates HTTPS URLs, rejects shell metachars
  * 100MB size guard, 90s clone timeout
  * auto-detects index.html in dist/public/build/_site/site/docs/out/www
- bot v2.4.0: i18n.py + lang/{en,ru}.json, /lang command, language toggle button
- bot: custom git template via text input with waiter gating

.gitignore

@@ -1,29 +0,0 @@
-# Environment
-.env
-*.env.local
-
-# Python
-__pycache__/
-*.pyc
-venv/
-.venv/
-
-# Backups (contain secrets)
-backups/
-*.tar.gz
-*.tar.gz.enc
-*.sha256
-
-# Temp
-/tmp/
-*.tmp
-*.swp
-
-# IDE
-.vscode/
-.idea/
-*.code-workspace
-
-# OS
-.DS_Store
-Thumbs.db