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/integration_hook.go

@@ -0,0 +1,105 @@
+package model
+
+import (
+	"database/sql/driver"
+	"encoding/json"
+	"fmt"
+	"time"
+
+	"gorm.io/datatypes"
+	"gorm.io/gorm"
+)
+
+// ===========================
+// Integration Hook types
+// ===========================
+// NOTE: HookType and HookStatus are declared in enums.go; additional HookType
+// constants for integration hooks (webhook/slack/shopify/linear/notion) are
+// also in enums.go.
+
+// IntegrationHook represents a third-party integration hook configuration.
+// Reference: Chatwoot Integrations::Hook — webhook/app integration bindings
+// Each hook belongs to an account and optionally to an inbox (for channel-specific integrations).
+// Hooks store provider-specific settings in the `settings` JSONB field.
+type IntegrationHook struct {
+	ID          uint           `gorm:"primaryKey;autoIncrement" json:"id"`
+	AccountID   uint           `gorm:"not null;index" json:"account_id"`
+	AppID       string         `gorm:"size:100;index" json:"app_id,omitempty"`
+	InboxID     *uint          `gorm:"index" json:"inbox_id,omitempty"` // nil = account-level hook
+	Inbox       *Inbox         `gorm:"foreignKey:InboxID" json:"inbox,omitempty"`
+	HookType    HookType       `gorm:"size:50;not null;index" json:"hook_type"`            // webhook/slack/shopify/linear/notion
+	Status      HookStatus     `gorm:"size:20;default:'active'" json:"status"`             // active/inactive
+	URL         string         `gorm:"size:1024" json:"url"`                               // webhook callback URL
+	AccessToken string         `gorm:"size:256;uniqueIndex" json:"access_token,omitempty"` // API token for the hook
+	ReferenceID string         `gorm:"size:255" json:"reference_id,omitempty"`
+	Settings    datatypes.JSON `gorm:"type:jsonb" json:"settings"` // provider-specific config (Slack channel_id, Shopify shop_domain, etc.)
+	CreatedAt   time.Time      `gorm:"autoCreateTime" json:"created_at"`
+	UpdatedAt   time.Time      `gorm:"autoUpdateTime" json:"updated_at"`
+	DeletedAt   gorm.DeletedAt `gorm:"index" json:"deleted_at,omitempty"`
+}
+
+// IntegrationApp represents an available integration app definition.
+// Reference: Chatwoot Integrations::App — catalog of supported integrations
+type IntegrationApp struct {
+	ID          uint      `gorm:"primaryKey;autoIncrement" json:"id"`
+	Name        string    `gorm:"size:255;not null" json:"name"`
+	Description string    `gorm:"size:512" json:"description"`
+	HookType    HookType  `gorm:"size:50;not null;uniqueIndex" json:"hook_type"`
+	Icon        string    `gorm:"size:512" json:"icon"`        // icon URL or CSS class
+	ActionURL   string    `gorm:"size:1024" json:"action_url"` // frontend action URL for the integration setup page
+	Enabled     bool      `gorm:"default:true" json:"enabled"` // whether the integration is available for installation
+	CreatedAt   time.Time `gorm:"autoCreateTime" json:"created_at"`
+	UpdatedAt   time.Time `gorm:"autoUpdateTime" json:"updated_at"`
+}
+
+// SlackSettings holds Slack integration-specific configuration.
+// Reference: Chatwoot Integrations::SlackController settings
+type SlackSettings struct {
+	ChannelID   string `json:"channel_id"`
+	ChannelName string `json:"channel_name"`
+	SlackToken  string `json:"slack_token,omitempty"`
+}
+
+// ShopifySettings holds Shopify integration-specific configuration.
+// Reference: Chatwoot Integrations::ShopifyController settings
+type ShopifySettings struct {
+	ShopDomain  string `json:"shop_domain"`
+	AccessToken string `json:"access_token,omitempty"`
+}
+
+// LinearSettings holds Linear integration-specific configuration.
+// Reference: Chatwoot Integrations::LinearController settings
+type LinearSettings struct {
+	TeamID      string `json:"team_id"`
+	TeamName    string `json:"team_name"`
+	AccessToken string `json:"access_token,omitempty"`
+	ProjectID   string `json:"project_id,omitempty"`
+}
+
+// NotionSettings holds Notion integration-specific configuration.
+type NotionSettings struct {
+	DatabaseID  string `json:"database_id,omitempty"`
+	AccessToken string `json:"access_token,omitempty"`
+}
+
+// HookSettingsMap is a JSON type for IntegrationHook.Settings that implements driver.Valuer/sql.Scanner.
+type HookSettingsMap map[string]interface{}
+
+func (h HookSettingsMap) Value() (driver.Value, error) {
+	if h == nil {
+		return json.Marshal(map[string]interface{}{})
+	}
+	return json.Marshal(h)
+}
+
+func (h *HookSettingsMap) Scan(value interface{}) error {
+	if value == nil {
+		*h = HookSettingsMap{}
+		return nil
+	}
+	bytes, ok := value.([]byte)
+	if !ok {
+		return fmt.Errorf("failed to unmarshal HookSettingsMap: %v", value)
+	}
+	return json.Unmarshal(bytes, h)
+}