Three stores, three importers and three pickers that differ only in their type are one of each (#85)

Refactoring round one: HttpFontStore/HttpSoundStore/HttpTextureStore collapse into a generic
HttpFileStore over a FileStore contract; fontImport/soundImport/textureImport share assetImport
with an ImportKind per sort; ImagePicker/FontPicker/SoundPicker sit on FilePicker and describe
only their row. The group/comment drag logic leaves GraphCanvas for annotationDrag.ts (with its
own unit test), declaredRows.ts replaces the duplicated row build in particles.ts and shaders.ts,
and dead code in font/sound/compile/emission/transform/actions is gone. README: asset list,
check count 958, the two-job CI, the Scenes wiki page.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

README.md

@@ -13,7 +13,8 @@ way in.
 ## In one screen
 
 - An **asset** is a named, typed thing (scene, camera, sprite, text, behavior, collider, container,
-  texture, animation, state machine) with properties and no position.
+  texture, font, sound, animation, state machine, shader, particles, variables) with properties and
+  no position.
 - A **scene object** places an asset: position, sparse **overrides** of its properties, an optional
   parent. Only what differs from the asset is stored; the inspector paints it gold and offers ↺ / ↑.
 - A **container** is a reusable group edited once and placed many times; its content is resolved
@@ -37,14 +38,14 @@ npm run build        # writes dist/ and regenerates index.html; the folder is wh
 The browser suite and the three example games need a machine with a GPU:
 
 ```bash
-node tools/seed-e2e.mjs && node tools/e2e.mjs      # the editor, 862 checks (GM_STEPS=20 for one step)
+node tools/seed-e2e.mjs && node tools/e2e.mjs      # the editor, 958 checks (GM_STEPS=20 for one step)
 node tools/seed-jumprun.mjs && node tools/smoke-jumprun.mjs
 node tools/seed-tetris.mjs && node tools/smoke-tetris.mjs
 node tools/seed-actor.mjs && node tools/smoke-actor.mjs
 ```
 
-Every push runs all of it on the Gitea runner, so locally take the gate plus the step your change
-touches and leave the full run to CI. Details, the GPU requirement and the detached runner are in
+Every push runs all of it on the Gitea runner – the gate as one job, build and suite as another
+beside it – so locally take the gate plus the step your change touches and leave the full run to CI. Details, the GPU requirement and the detached runner are in
 [Development](https://git.nockal.com/meleki/game-maker/wiki/Development).
 
 ## Documentation
@@ -52,11 +53,16 @@ touches and leave the full run to CI. Details, the GPU requirement and the detac
 | Page | What it covers |
 |---|---|
 | [Concepts](https://git.nockal.com/meleki/game-maker/wiki/Concepts) | Assets, scene objects, overrides, play mode, the camera, the console |
+| [Scenes](https://git.nockal.com/meleki/game-maker/wiki/Scenes) | The edited scene, the start scene, and switching scenes from a graph |
 | [Scene editing](https://git.nockal.com/meleki/game-maker/wiki/Scene-editing) | Placing, z-order, hierarchy, the editor offset |
 | [Behaviors](https://git.nockal.com/meleki/game-maker/wiki/Behaviors) | Node graphs: variables, the node set, structs and lists, loops, nesting, editing |
 | [Colliders](https://git.nockal.com/meleki/game-maker/wiki/Colliders) | Collision events and blocking movement |
-| [Textures](https://git.nockal.com/meleki/game-maker/wiki/Textures) | Images, frames, the filter, upload limits |
+| [Textures](https://git.nockal.com/meleki/game-maker/wiki/Textures) | Images, frames, nine-slice, the filter, upload limits |
+| [Fonts](https://git.nockal.com/meleki/game-maker/wiki/Fonts) | Font assets, the picker, what a text falls back to |
+| [Sounds](https://git.nockal.com/meleki/game-maker/wiki/Sounds) | Sound assets and `Play sound` |
 | [Animations](https://git.nockal.com/meleki/game-maker/wiki/Animations) | Animation assets and the Animation tab |
+| [Shaders](https://git.nockal.com/meleki/game-maker/wiki/Shaders) | Shader graphs a sprite wears, their node set, the properties they declare |
+| [Particles](https://git.nockal.com/meleki/game-maker/wiki/Particles) | Particle graphs: a particle as a function of its age |
 | [State machines](https://git.nockal.com/meleki/game-maker/wiki/State-machines) | The asset, named transitions, `State branch`, `Set state` and `State transition` |
 | [Containers](https://git.nockal.com/meleki/game-maker/wiki/Containers) | Templates, instances, screens |
 | [Keyboard](https://git.nockal.com/meleki/game-maker/wiki/Keyboard) | Every shortcut |