Odoo ERP ported to Go — complete backend + original OWL frontend

Full port of Odoo's ERP system from Python to Go, with the original
Odoo JavaScript frontend (OWL framework) running against the Go server.

Backend (10,691 LoC Go):
- Custom ORM: CRUD, domains→SQL with JOINs, computed fields, sequences
- 93 models across 14 modules (base, account, sale, stock, purchase, hr,
  project, crm, fleet, product, l10n_de, google_address/translate/calendar)
- Auth with bcrypt + session cookies
- Setup wizard (company, SKR03 chart, admin, demo data)
- Double-entry bookkeeping constraint
- Sale→Invoice workflow (confirm SO → generate invoice → post)
- SKR03 chart of accounts (110 accounts) + German taxes (USt/VSt)
- Record rules (multi-company filter)
- Google integrations as opt-in modules (Maps, Translate, Calendar)

Frontend:
- Odoo's original OWL webclient (503 JS modules, 378 XML templates)
- JS transpiled via Odoo's js_transpiler (ES modules → odoo.define)
- SCSS compiled to CSS (675KB) via dart-sass
- XML templates compiled to registerTemplate() JS calls
- Static file serving from Odoo source addons
- Login page, session management, menu navigation
- Contacts list view renders with real data from PostgreSQL

Infrastructure:
- 14MB single binary (CGO_ENABLED=0)
- Docker Compose (Go server + PostgreSQL 16)
- Zero phone-home (no outbound calls to odoo.com)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

addons/google_calendar/module.go

@@ -0,0 +1,27 @@
+// Package google_calendar provides Google Calendar sync integration.
+// OPT-IN: Only active when GOOGLE_CALENDAR_API_KEY is configured.
+//
+// Features:
+// - Sync events between Odoo and Google Calendar
+// - Create Google Calendar events from project tasks
+// - Import Google Calendar events as activities
+package google_calendar
+
+import (
+	"odoo-go/addons/google_calendar/models"
+	"odoo-go/pkg/modules"
+)
+
+func init() {
+	modules.Register(&modules.Module{
+		Name:        "google_calendar",
+		Description: "Google Calendar Sync",
+		Version:     "19.0.1.0.0",
+		Category:    "Integration",
+		Depends:     []string{"base"},
+		Application: false,
+		Installable: true,
+		Sequence:    100,
+		Init:        models.Init,
+	})
+}