chore(github): generic example.com in docs, remove mirror scripts

Replace sac.kalinamall.ru with sac.example.com in public docs/deploy.
Remove Push-Mirror and Rewrite-GitHostUrls scripts from repo.
Simplify workspace-three-repos.md for GitHub-only workflow.

Co-authored-by: Cursor <cursoragent@cursor.com>

docs/work-plan.md

@@ -9,7 +9,7 @@
 | # | Задача | Статус |
 |---|--------|--------|
 | 0.1–0.3 | ТЗ, архитектура, схема, deployment | ✅ |
-| 0.5 | Репозиторий GitHub + зеркало kalinamall | ✅ |
+| 0.5 | Репозиторий GitHub + prod deployment | ✅ |
 | 0.6 | Multi-root workspace | ✅ |
 
 ---
@@ -37,7 +37,7 @@
 |---|--------|--------|
 | 1B.1 | Scaffold backend FastAPI | ✅ |
 | 1B.2 | PostgreSQL + Alembic (hosts, events, api_keys) | ✅ |
-| 1B.3 | `POST /api/v1/events`, `GET /health` | ✅ prod `sac.kalinamall.ru` |
+| 1B.3 | `POST /api/v1/events`, `GET /health` | ✅ prod `sac.example.com` |
 | 1B.4 | systemd + nginx + TLS | ✅ |
 | 1B.5 | Валидация JSON Schema v1 | ✅ |
 
@@ -90,7 +90,7 @@
 - [x] `d2-1` UI Problems: список, фильтры, `Ack/Resolve`, карточка с таймлайном
 - [x] `d2-2` Dashboard: top hosts/types, `open vs resolved 24h`, drill-down
 - [x] `d2-3` Ops: retention, health checks, runbook backup/restore/deploy
-- [x] `dod` DoD: нет дублей `event_id`, Problems e2e, 3 правила, UI MVP, docs, push в kalinamall
+- [x] `dod` DoD: нет дублей `event_id`, Problems e2e, 3 правила, UI MVP, docs, push в prod
 
 ### Отображение хостов (`display_name`, как `SERVER_DISPLAY_NAME` у ssh)
 
@@ -122,7 +122,7 @@
 - [x] `14:30–16:00` Dashboard: `open/resolved 24h` + drill-down
 - [x] `16:00–17:00` retention job (`events 30–90d`, `problems 180d+`)
 - [x] `17:00–18:00` health checks (DB/worker/heartbeat stale)
-- [x] `18:00–19:00` runbook + финальный push в kalinamall + freeze dev
+- [x] `18:00–19:00` runbook + финальный push в prod + freeze dev
 
 ### Неделя после freeze (только тестирование)