Feat v0.9.5 typed forms SDK primitive

Extract typed form system from models/workflow.go into standalone
server/forms/ package. Any package can now declare and validate
forms, not just workflow stages.

- New server/forms/ package (types + validation + condition evaluator)
- REST POST /api/v1/forms/validate endpoint
- Starlark forms.validate(template, data) module
- Frontend sw.forms.render(), .validate(), .validateRemote()
- Manifest form_template accepted at package level
- 16 new tests (12 forms + 4 Starlark module)

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

server/sandbox/forms_module_test.go

@@ -0,0 +1,116 @@
+package sandbox
+
+import (
+	"context"
+	"testing"
+
+	"go.starlark.net/starlark"
+)
+
+func runFormsScript(t *testing.T, script string) starlark.StringDict {
+	t.Helper()
+	mod := BuildFormsModule(context.Background())
+	predeclared := starlark.StringDict{"forms": mod}
+	globals, err := starlark.ExecFile(&starlark.Thread{Name: "test"}, "test.star", script, predeclared)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return globals
+}
+
+func TestFormsModule_ValidateValid(t *testing.T) {
+	globals := runFormsScript(t, `
+tpl = {
+    "fields": [
+        {"key": "name", "type": "text", "label": "Name", "required": True},
+        {"key": "email", "type": "email", "label": "Email"},
+    ]
+}
+result = forms.validate(tpl, {"name": "Alice", "email": "alice@example.com"})
+`)
+	result := globals["result"].(*starlark.Dict)
+	valid, _, _ := result.Get(starlark.String("valid"))
+	if valid != starlark.True {
+		t.Fatalf("expected valid=True, got %v", valid)
+	}
+	errors, _, _ := result.Get(starlark.String("errors"))
+	errList := errors.(*starlark.List)
+	if errList.Len() != 0 {
+		t.Fatalf("expected 0 errors, got %d", errList.Len())
+	}
+}
+
+func TestFormsModule_ValidateRequired(t *testing.T) {
+	globals := runFormsScript(t, `
+tpl = {
+    "fields": [
+        {"key": "name", "type": "text", "label": "Name", "required": True},
+    ]
+}
+result = forms.validate(tpl, {})
+`)
+	result := globals["result"].(*starlark.Dict)
+	valid, _, _ := result.Get(starlark.String("valid"))
+	if valid != starlark.False {
+		t.Fatalf("expected valid=False, got %v", valid)
+	}
+	errors, _, _ := result.Get(starlark.String("errors"))
+	errList := errors.(*starlark.List)
+	if errList.Len() != 1 {
+		t.Fatalf("expected 1 error, got %d", errList.Len())
+	}
+	errDict := errList.Index(0).(*starlark.Dict)
+	key, _, _ := errDict.Get(starlark.String("key"))
+	if key.(starlark.String).GoString() != "name" {
+		t.Fatalf("expected error key 'name', got %v", key)
+	}
+}
+
+func TestFormsModule_ValidateTypeErrors(t *testing.T) {
+	globals := runFormsScript(t, `
+tpl = {
+    "fields": [
+        {"key": "age", "type": "number", "label": "Age", "validation": {"min": 0, "max": 150}},
+        {"key": "email", "type": "email", "label": "Email"},
+    ]
+}
+result = forms.validate(tpl, {"age": -5, "email": "bad"})
+`)
+	result := globals["result"].(*starlark.Dict)
+	valid, _, _ := result.Get(starlark.String("valid"))
+	if valid != starlark.False {
+		t.Fatalf("expected valid=False, got %v", valid)
+	}
+	errors, _, _ := result.Get(starlark.String("errors"))
+	errList := errors.(*starlark.List)
+	if errList.Len() != 2 {
+		t.Fatalf("expected 2 errors, got %d", errList.Len())
+	}
+}
+
+func TestFormsModule_ValidateCondition(t *testing.T) {
+	globals := runFormsScript(t, `
+tpl = {
+    "fields": [
+        {"key": "type", "type": "text", "label": "Type"},
+        {"key": "details", "type": "text", "label": "Details", "required": True,
+         "condition": {"when": "type", "op": "eq", "value": "other"}},
+    ]
+}
+# Condition not met — details not required
+result1 = forms.validate(tpl, {"type": "normal"})
+# Condition met — details required
+result2 = forms.validate(tpl, {"type": "other"})
+`)
+	result1 := globals["result1"].(*starlark.Dict)
+	valid1, _, _ := result1.Get(starlark.String("valid"))
+	if valid1 != starlark.True {
+		t.Fatalf("result1: expected valid=True, got %v", valid1)
+	}
+
+	result2 := globals["result2"].(*starlark.Dict)
+	valid2, _, _ := result2.Get(starlark.String("valid"))
+	if valid2 != starlark.False {
+		t.Fatalf("result2: expected valid=False, got %v", valid2)
+	}
+}