Switch to VectorEngine gpt-image-2 and edits

Replace uses of the legacy `gpt-image-2-all` model with `gpt-image-2` and standardize image workflows: no-reference generation uses POST /v1/images/generations, any-reference flows use POST /v1/images/edits with multipart `image` parts. Update SKILLs, generation scripts, decision logs, and docs to reflect the contract change and edits-vs-generations guidance. Apply corresponding changes across backend (api-server match3d/puzzle modules, openai image adapter, mappers, telemetry, spacetime client/module), frontend components and services (Match3D, Puzzle, CreativeImageInputPanel, runtime shells), and add new spritesheet/parser files and tests. Also add media/logo.png. These changes align repository code and documentation with the VectorEngine image API contract and update generation/upload handling (green-screen -> alpha processing, spritesheet handling, and related tests).

.codex/skills/gpt-image-2-apimart/scripts/generate-template-samples.mjs

@@ -211,7 +211,7 @@ async function downloadUrl(url, timeoutMs) {
 
 async function generateOne(env, template, outDir) {
   const requestBody = {
-    model: 'gpt-image-2-all',
+    model: 'gpt-image-2',
     prompt: buildPrompt(template),
     n: 1,
     size: '1024x1024',
@@ -275,7 +275,7 @@ if (dryRun) {
           id: template.id,
           title: template.title,
           body: {
-            model: 'gpt-image-2-all',
+            model: 'gpt-image-2',
             prompt: buildPrompt(template),
             n: 1,
             size: '1024x1024',