Reorganize repo: backend/, deploy/, docs/ layout + AGENTS.md

Restructure the monorepo into clear top-level directories:
- backend/: Go module root (cmd, internal, pkg, configs, migrations,
  docs/swagger, scripts, tests, go.mod, Makefile, .air.toml)
- deploy/: Docker (Dockerfile, docker-compose*), quickstart, fluentd
- docs/: project documentation + reports/ (moved from repo root)
- AGENTS.md: new AI coding-agent guide at repo root

Update all references to the new layout:
- Dockerfile: COPY backend/go.mod, COPY backend/ (context = repo root)
- docker-compose files: context ../.., dockerfile deploy/docker/Dockerfile,
  env_file ../../.env, volume mounts ../../backend:/app
- deploy/quickstart/compose.yaml: dockerfile deploy/docker/Dockerfile
- CI: working-directory: backend for go commands, file deploy/docker/Dockerfile,
  coverage path backend/coverage.out, health_check backend/scripts/
- backend/Makefile: docker target uses -f ../deploy/docker/Dockerfile ../
- README: architecture tree, quickstart, config paths updated

Move root stray scripts (rename_models.*, run_m11_tests.sh, verify_build.sh,
gorm_bool_main.go) to backend/scripts/legacy/. All moves via git mv to
preserve history. Build, vet, SQLite tests, and docker compose config verified.

backend/internal/model/bot_rule.go

@@ -0,0 +1,21 @@
+package model
+
+// ===========================
+// AgentBot Rule Engine — thin wrappers over automation package types
+// ===========================
+// The actual model definitions live in the automation package to avoid
+// the import cycle: model → automation → channel → model.
+// This file provides convenience aliases and response shapes that the
+// handler/service layer can use without importing automation directly.
+
+// BotRule is an alias for automation.BotRule — use automation.BotRule directly.
+// This alias exists only for backward compatibility with any code that
+// references model.BotRule. New code should import automation.BotRule.
+//
+// NOTE: We cannot define a type alias here because it would require
+// importing the automation package, which creates the cycle:
+//   model → automation → channel → model
+//
+// Therefore, all BotRule and BotTriggerConfig types live exclusively
+// in the automation package. Handlers and services should import
+// "github.com/gochat/gochat/internal/automation" directly.