Feat v0.9.2 Starlark converter consolidation + snapshot cleanup (#75)

Consolidate duplicate Go↔Starlark converters into sandbox/convert.go
and snapshot parsers into models/snapshot.go. Standardize snapshot
creation on wrapped format. Net -393 lines across 21 files.

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

server/handlers/workflow_hooks_test.go

@@ -5,6 +5,8 @@ import (
 	"testing"
 
 	"go.starlark.net/starlark"
+
+	"armature/sandbox"
 )
 
 // ── parseOnAdvanceResult ────────────────────
@@ -82,7 +84,7 @@ func TestParseOnAdvanceResult_EmptyDict(t *testing.T) {
 	}
 }
 
-// ── starlarkDictToMap ───────────────────────
+// ── DictToMap ───────────────────────
 
 func TestStarlarkDictToMap_NestedStructure(t *testing.T) {
 	inner := starlark.NewDict(1)
@@ -98,7 +100,7 @@ func TestStarlarkDictToMap_NestedStructure(t *testing.T) {
 	_ = outer.SetKey(starlark.String("nested"), inner)
 	_ = outer.SetKey(starlark.String("members"), members)
 
-	m := starlarkDictToMap(outer)
+	m := sandbox.DictToMap(outer)
 
 	if m["title"] != "Test" {
 		t.Errorf("expected title='Test', got %v", m["title"])