Complete ORM core: _inherits, Related write-back, Copy, constraints

Batch 1 (quick-fixes):
- Field.Copy attribute + IsCopyable() method for copy control
- Constraints now run in Write() (was only Create — bug fix)
- Readonly fields silently skipped in Write()
- active_test: auto-filter archived records in Search()

Batch 2 (Related field write-back):
- preprocessRelatedWrites() follows FK chain and writes to target model
- Enables Settings page to edit company name/address/etc.
- Loop protection via _write_related_depth context counter

Batch 3 (_inherits delegation):
- SetupAllInherits() generates Related fields from parent models
- preprocessInheritsCreate() auto-creates parent records on Create
- Declared on res.users, res.company, product.product
- Called in LoadModules before compute setup

Batch 4 (Copy method):
- Recordset.Copy(defaults) with blacklist, IsCopyable check
- M2M re-linking, rec_name "(copy)" suffix
- Replaces simplified copy case in server dispatch

Batch 5 (Onchange compute):
- RunOnchangeComputes() triggers dependent computes on field change
- Virtual record (ID=-1) with client values in cache
- Integrated into onchange RPC handler

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

pkg/orm/field.go

@@ -60,6 +60,9 @@ type Field struct {
 	// Translation
 	Translate bool // Field supports multi-language
 
+	// Copy
+	Copy bool // Whether this field is copied on record duplication
+
 	// Groups (access control)
 	Groups string // Comma-separated group XML IDs
 
@@ -97,6 +100,27 @@ func (f *Field) IsStored() bool {
 	return f.Type.IsStored()
 }
 
+// IsCopyable returns true if this field should be copied on record duplication.
+// Mirrors: odoo/orm/fields.py Field.copy
+func (f *Field) IsCopyable() bool {
+	// If explicitly set, use that
+	if f.Copy {
+		return true
+	}
+	// Defaults: non-copyable for computed, O2M, id, timestamps
+	if f.Name == "id" || f.Name == "create_uid" || f.Name == "create_date" ||
+		f.Name == "write_uid" || f.Name == "write_date" || f.Name == "password" {
+		return false
+	}
+	if f.Compute != "" && !f.Store {
+		return false
+	}
+	if f.Type == TypeOne2many {
+		return false
+	}
+	return true
+}
+
 // IsRelational returns true for relational field types.
 func (f *Field) IsRelational() bool {
 	return f.Type.IsRelational()
@@ -130,6 +154,7 @@ type FieldOpts struct {
 	OnDelete      OnDelete
 	CurrencyField string
 	Translate     bool
+	Copy          bool
 	Groups        string
 }
 
@@ -160,6 +185,7 @@ func newField(name string, typ FieldType, opts FieldOpts) *Field {
 		OnDelete:      opts.OnDelete,
 		CurrencyField: opts.CurrencyField,
 		Translate:     opts.Translate,
+		Copy:          opts.Copy,
 		Groups:        opts.Groups,
 		column:        name,
 	}