feat: Portal, Email Inbound, Discuss + module improvements

- Portal: /my/* routes, signup, password reset, portal user support
- Email Inbound: IMAP polling (go-imap/v2), thread matching
- Discuss: mail.channel, long-polling bus, DM, unread count
- Cron: ir.cron runner (goroutine scheduler)
- Bank Import, CSV/Excel Import
- Automation (ir.actions.server)
- Fetchmail service
- HR Payroll model
- Various fixes across account, sale, stock, purchase, crm, hr, project

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

addons/mail/module.go

@@ -0,0 +1,22 @@
+// Package mail implements Odoo's Mail/Chatter module.
+// Mirrors: odoo/addons/mail/__manifest__.py
+package mail
+
+import (
+	"odoo-go/addons/mail/models"
+	"odoo-go/pkg/modules"
+)
+
+func init() {
+	modules.Register(&modules.Module{
+		Name:        "mail",
+		Description: "Discuss",
+		Version:     "19.0.1.0.0",
+		Category:    "Productivity/Discuss",
+		Depends:     []string{"base"},
+		Application: true,
+		Installable: true,
+		Sequence:    5,
+		Init:        models.Init,
+	})
+}