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).

server-rs/crates/api-server/src/match3d/vector_engine_gemini.rs

@@ -27,6 +27,8 @@ pub(super) async fn generate_match3d_material_sheet(
     Ok(Match3DMaterialSheet {
         task_id: generated.task_id,
         prompt,
+        image_src: None,
+        image_object_key: None,
         image,
     })
 }