Added config editor in front end

src/README.md

@@ -65,7 +65,8 @@ Included now:
 - background Slang compile of `shaders/happy-accident`
 - app-owned display/render layer model for shader build readiness
 - app-owned submission of a completed shader artifact
-- render-thread-owned runtime render scene for ready shader layers
+- render-thread-owned render-content interface with runtime shader content as the default implementation
+- render-thread-owned runtime render scene for ready shader layers inside the default render-content adapter
 - shared-context GL prepare worker for runtime shader program compile/link
 - render-thread-only GL program swap once a prepared program is ready
 - manifest-driven stateless single-pass shader packages
@@ -221,6 +222,8 @@ Currently consumed fields:
 
 `output.pixelFormat=auto` chooses UYVY8 for DeckLink/NDI output unless alpha output is required, in which case it uses BGRA8. Explicit `uyvy8` requests are rejected back to BGRA8 when alpha is required. V210/YUVA remain explicit unsupported render-readback states until matching render-thread packers exist.
 
+The control UI includes a host-config editor backed by `GET /api/config` and `POST /api/config/save`. Saving rewrites `config/runtime-host.json` and marks the app as needing restart. Startup-owned services such as render dimensions, video backend selection, frame rate, output pixel format, HTTP port, and preview settings apply after `POST /api/app/restart` starts a fresh native host process.
+
 When `previewEnabled` is true, the preview window runs on `PreviewWindowThread`. It paints BGRA8 system-memory frames directly and decodes UYVY8 frames to BGRA for Win32/GDI after render readback has already completed, so it does not bind GL and does not consume frames from video output. `previewFps` controls the preview repaint cadence; the default is 60 fps and `config/runtime-host.json` tracks the shipped 59.94 output cadence.
 
 The loaded config is treated as a read-only startup snapshot. Subsystems that need config should receive this snapshot or a narrowed config struct from app orchestration; they should not reload files independently.
@@ -391,7 +394,7 @@ The `/api/state` shader list uses the same support rules as runtime shader compi
 
 Runtime shaders are exposed through `RuntimeLayerModel` as display layers with manifest parameter definitions, current parameter values, build status, and render-ready artifacts. POST controls mutate this app-owned model and may start background shader builds when the selected shader changes or when `/api/reload` is requested. Durable UI/API layer changes request a debounced background write to `runtime/runtime_state.json`. OSC ingress is not wired yet; when it is added, OSC-driven changes should stay out of autosave unless an explicit persistence policy is introduced.
 
-When a layer becomes render-ready, the app publishes the ready render-layer snapshot to the render thread. The render thread owns the GL-side `RuntimeRenderScene`, diffs that snapshot at a frame boundary, queues new or changed pass programs to the shared-context prepare worker, swaps in a full prepared render plan only after every pass is ready, removes obsolete GL programs, and renders ready layers in order. Stacked stateless full-frame shaders render through internal ping-pong targets so each layer can sample the previous layer through `gLayerInput`; multipass shaders route named intermediate outputs through their manifest-declared pass inputs, and the final ready layer renders to the output target.
+When a layer becomes render-ready, the app publishes the ready render-layer snapshot to the render thread. The render thread forwards those snapshots to `RuntimeShaderRenderContent`, the default `IRenderContent` implementation. That adapter owns the GL-side `RuntimeRenderScene`, diffs snapshots at a frame boundary, queues new or changed pass programs to the shared-context prepare worker, swaps in a full prepared render plan only after every pass is ready, removes obsolete GL programs, and renders ready layers in order. Stacked stateless full-frame shaders render through internal ping-pong targets so each layer can sample the previous layer through `gLayerInput`; multipass shaders route named intermediate outputs through their manifest-declared pass inputs, and the final ready layer renders to the output target.
 
 Successful handoff signs:
 
@@ -441,11 +444,13 @@ This app keeps the same core behavior but splits it into modules that can grow:
 
 - `frames/`: system-memory handoff
 - `platform/`: COM/Win32/hidden GL context support
-- `render/`: cadence thread, clock, and simple renderer
+- `render/`: cadence thread, clock, render-content boundary, and default runtime shader content
 - `frames/InputFrameMailbox`: non-blocking bounded FIFO CPU input handoff with contiguous-copy fast path for matching row strides
 - `render/InputFrameTexture`: render-thread-owned upload of the currently acquired CPU input frame into GL, including raw UYVY8 decode into the shader-visible input texture
 - `render/readback/`: PBO-backed BGRA8/UYVY8 readback and completed-frame publication
 - `render/thread/`: render thread lifecycle, GL startup/cadence loop, metrics, and runtime layer commit mailbox
+- `render/RenderContent`: narrow draw-call boundary used by the cadence/readback shell
+- `render/RuntimeShaderRenderContent`: default content adapter that wraps runtime shader rendering and fallback presentation
 - `render/runtime/RuntimeRenderScene`: render-thread-owned GL scene for ready runtime shader layers
 - `render/runtime/RuntimeShaderPrepareWorker`: shared-context runtime shader program compile/link worker
 - `runtime/catalog/`: supported shader catalog and package filtering
@@ -466,8 +471,6 @@ This app keeps the same core behavior but splits it into modules that can grow:
 
 Only after this app matches the probe's smooth output:
 
-1. replace `SimpleMotionRenderer` with a render-scene interface
-2. port shader package rendering
-3. broaden runtime snapshots/live state toward OSC and presets
-4. add screenshot capture from system-memory frames
-5. add scaling and additional input format support after the BGRA8/raw-UYVY8 input edge is stable
+1. broaden runtime snapshots/live state toward OSC and presets
+2. add screenshot capture from system-memory frames
+3. add scaling and additional input format support after the BGRA8/raw-UYVY8 input edge is stable