doc updates

README.md

@@ -2,7 +2,7 @@
 
 Native video shader host with an OpenGL render path, pluggable video I/O boundary, DeckLink backend, Slang shader packages, and a local React control UI.
 
-The app loads shader packages from `shaders/`, compiles Slang to GLSL at runtime, renders a configurable layer stack, and exposes a browser-based control surface over a local HTTP/WebSocket server.
+The app loads shader packages from `shaders/`, compiles Slang to GLSL at runtime, renders a configurable layer stack, and exposes a browser-based control surface over a local HTTP/WebSocket server. Shader compilation is prepared off the frame path where possible, then committed on the render thread so editing shader files does not block video output for the whole compile.
 
 ## Repository Layout
 
@@ -62,6 +62,14 @@ npm run build
 
 The native app serves `ui/dist` when it exists, otherwise it falls back to the source UI directory during development.
 
+The control UI provides:
+
+- A searchable shader library for adding layers.
+- Compact parameter rows with inline descriptions and OSC copy controls.
+- Stack save/recall presets.
+- Manual shader reload.
+- Screenshot capture from the final output render target.
+
 ## Package
 
 Build the UI, build the native Release target, then install into a portable runtime folder:
@@ -123,6 +131,7 @@ Current native test coverage includes:
 - Shader manifest parsing, temporal manifest validation, and package registry scanning.
 - Video I/O format helpers, v210/Ay10 row-byte math, v210 pack/unpack math, playout scheduler timing, and fake backend contract coverage.
 - OSC packet parsing.
+- Slang validation for every available shader package.
 
 ## Runtime Configuration
 
@@ -182,7 +191,11 @@ http://127.0.0.1:<serverPort>/docs
 
 Use those docs to inspect the `/api/state`, layer control, stack preset, and reload endpoints. Live state updates are also sent over the `/ws` WebSocket.
 
-The control UI also has a Screenshot button. It queues a capture of the final output render target and writes a PNG under:
+The control UI has a **Reload shaders** button. It rescans `shaders/`, re-reads manifests, queues shader compilation, refreshes shader availability/errors, and keeps the previous working shader stack running if a changed shader fails to compile.
+
+Each parameter row also includes a small **OSC** button. Clicking it copies that parameter's OSC route to the clipboard.
+
+The control UI also has a **Screenshot** button. It queues a capture of the final output render target and writes a PNG under:
 
 ```text
 runtime/screenshots/
@@ -210,7 +223,7 @@ shaders/<id>/
   optional-font-or-texture-assets
 ```
 
-See `SHADER_CONTRACT.md` for the manifest schema, parameter types, texture assets, font/text assets, temporal history support, optional render-pass declarations, and the Slang entry point contract. `shaders/text-overlay/` is the reference live text package and bundles Roboto Regular with its OFL license.
+See `SHADER_CONTRACT.md` for the manifest schema, parameter types, texture assets, font/text assets, temporal history support, optional render-pass declarations, and the Slang entry point contract. `shaders/text-overlay/` is the reference live text package and bundles Roboto Regular with its OFL license. Broken shader packages are shown as unavailable in the selector with their error text instead of preventing the app from launching.
 
 ## Generated Files
 
@@ -250,14 +263,13 @@ If `SLANG_ROOT` is not set, the workflow falls back to the repo-local default un
 
 - Audio.
 - Genlock.
-- Find a better UI library for React.
 - Logs.
 - Add more video I/O backends now that the DeckLink path is behind `videoio/`.
 - Support a separate sound shader `.slang` file in shader packages. (https://www.shadertoy.com/view/XsBXWt)
-- Add WebView2
+- Add WebView2 for an embedded native control surface.
 - MSDF typography rasterisation
 - More shader-library organisation and filtering as the built-in library grows.
-- linear compositing?
+- Optional linear-light compositing mode.
 - compute shaders or a small 1x1 or nx1 RGBA16f render target for arbitrary data storage
 - allow shaders to read other shaders data store based on name? or output over OSC
 - Mipmapping for shader-declared textures