Initial workspace: GPU context, compute pass, adaptive Slint shell

Establishes the v0.1 foundations on both platforms:

- dr-types: SourceRef (never a filesystem path — Android SAF has none),
  Format, Availability, Validator with ETag quote normalisation
- dr-gpu: wgpu device, compute pass writing a storage texture, resize
- dr-ui: Slint shell with FR-UI-1 adaptive layout, computed in Rust to
  avoid a binding loop
- docker/android: pinned toolchain, verified producing API 28 ARM binaries

Measured the cost of the temporary CPU readback path (dr-gpu bench):
compute is 0.06-0.28ms across sizes while readback is 0.63-7.43ms, so
readback is 90-96% of frame time and scales with area. Recorded in
ARCH §6.1 — this is why spike S1 is the priority.

Mitigations pending S1: reuse the staging buffer, apply at most one
resize per frame, and cap render resolution at 2048 on the long edge.

10 tests passing; core crates cross-compile for aarch64-linux-android.

.claude/settings.json

@@ -0,0 +1,41 @@
+{
+  "permissions": {
+    "allow": [
+      "Bash(curl -s \"https://api.github.com/search/code?q=WrapTexture+org:Noesis\" -H \"Accept: application/vnd.github+json\")",
+      "Bash(curl -s \"https://api.github.com/orgs/Noesis/repos?per_page=100\")",
+      "WebFetch(domain:wiki.wxwidgets.org)",
+      "Bash(curl -sS \"https://gitlab.com/sciter-engine/sciter-js-sdk/-/raw/main/samples.gpu/hello-es-triangle.htm\")",
+      "Bash(curl -sS \"https://gitlab.com/api/v4/projects/sciter-engine%2Fsciter-js-sdk/repository/tree?path=include&recursive=true&per_page=100&ref=main\")",
+      "Bash(python3 -c ' *)",
+      "Bash(curl -sL --max-time 40 \"https://api.github.com/repos/wxWidgets/wxWidgets/contents/src?ref=master\")",
+      "Bash(curl -sL --max-time 40 \"https://api.github.com/repos/wxWidgets/wxWidgets/contents/include/wx/android?ref=master\")",
+      "Bash(curl -sL --max-time 40 -H \"Accept: application/vnd.github.text-match+json\" \"https://api.github.com/search/code?q=vulkan+repo:wxWidgets/wxWidgets\")",
+      "Bash(curl -sS \"https://gitlab.com/sciter-engine/sciter-js-sdk/-/raw/main/include/sciter-x-video-api.h\")",
+      "WebFetch(domain:docs.wxwidgets.org)",
+      "Bash(curl -sS \"https://gitlab.com/sciter-engine/sciter-js-sdk/-/raw/main/CHANGELOG.md\")",
+      "Bash(curl -sL --max-time 40 \"https://raw.githubusercontent.com/wxWidgets/wxWidgets/master/docs/readme.txt\")",
+      "Bash(curl -sL --max-time 40 \"https://raw.githubusercontent.com/wxWidgets/wxWidgets/master/docs/licence.txt\")",
+      "Bash(curl -sL --max-time 40 \"https://raw.githubusercontent.com/wxWidgets/wxWidgets/master/docs/licendu.txt\")",
+      "Bash(curl -sS \"https://gitlab.com/api/v4/projects/sciter-engine%2Fsciter-js-sdk/repository/tree?path=build&recursive=true&per_page=100&ref=main\")",
+      "Bash(curl -sS \"https://gitlab.com/sciter-engine/sciter-js-sdk/-/raw/main/premake5.lua\")",
+      "WebFetch(domain:slack-chats.kotlinlang.org)",
+      "Bash(curl -sS -L \"https://sciter.com/\")",
+      "Bash(curl -sL --max-time 45 \"https://api.github.com/orgs/ultralight-ux/repos?per_page=100&sort=pushed\")",
+      "Bash(curl -sL --max-time 40 \"https://gitlab.gnome.org/GNOME/gtk/-/raw/main/gdk/gdkdmabuftexturebuilder.h\")",
+      "Bash(curl -sL --max-time 40 \"https://gitlab.gnome.org/GNOME/gtk/-/raw/main/gdk/gdkgltexturebuilder.h\")",
+      "Bash(curl -sL --max-time 40 \"https://gitlab.gnome.org/api/v4/projects/GNOME%2Fgtk/repository/tree?path=gdk&ref=main&per_page=100\")",
+      "WebFetch(domain:docs.slint.dev)",
+      "WebFetch(domain:releases.slint.dev)",
+      "WebFetch(domain:flutter.dev)",
+      "Bash(curl -sS -L \"https://sciter.com/forums/topic/status-of-quark-sciter-lite-sciterjs-android-ios/\")",
+      "Bash(curl -sL --max-time 45 \"https://api.github.com/repos/ultralight-ux/AppCore/git/trees/master?recursive=1\")",
+      "Bash(curl -sL --max-time 40 \"https://gitlab.gnome.org/GNOME/gtk/-/raw/main/gdk/meson.build\")",
+      "WebFetch(domain:www.jetbrains.com)",
+      "Bash(curl -sS \"https://gitlab.com/api/v4/projects/sciter-engine%2Fsciter-js-sdk/repository/tree?path=demos.lite&recursive=true&per_page=100&ref=main\")",
+      "Bash(curl -sL --max-time 40 \"https://gitlab.gnome.org/api/v4/projects/GNOME%2Fgtk/repository/commits?path=gdk/android/gdkandroidglcontext.c&ref_name=main&per_page=20\")",
+      "Bash(curl -sL --max-time 40 \"https://gitlab.gnome.org/GNOME/gtk/-/raw/main/gdk/android/meson.build\")",
+      "WebFetch(domain:docs.sciter.com)",
+      "Bash(curl -sS -L \"https://sciter.com/support-of-displayflex-and-displaygrid-in-sciter/\")"
+    ]
+  }
+}