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/models/mail_followers.go

@@ -0,0 +1,31 @@
+package models
+
+import "odoo-go/pkg/orm"
+
+// initMailFollowers registers the mail.followers model.
+// Mirrors: odoo/addons/mail/models/mail_followers.py
+func initMailFollowers() {
+	m := orm.NewModel("mail.followers", orm.ModelOpts{
+		Description: "Document Followers",
+	})
+
+	m.AddFields(
+		orm.Char("res_model", orm.FieldOpts{
+			String:   "Related Document Model Name",
+			Required: true,
+			Index:    true,
+		}),
+		orm.Integer("res_id", orm.FieldOpts{
+			String:   "Related Document ID",
+			Required: true,
+			Index:    true,
+			Help:     "Id of the followed resource",
+		}),
+		orm.Many2one("partner_id", "res.partner", orm.FieldOpts{
+			String:   "Related Partner",
+			Required: true,
+			Index:    true,
+			OnDelete: orm.OnDeleteCascade,
+		}),
+	)
+}