gui_toolkit 0.45.0

Added

• Accessibility, node by node and several windows: platform.a11y_diff_patch sends a tree's changes from only the nodes that changed (a document that knows its mutations no longer makes its whole tree again); the children a node lost are forgotten with their subtrees, so a node put back goes whole. ui.a11y_cost(s) gives the nodes and the milliseconds of the last tree. A ui.State built for another window than its last one sends that window a whole tree. tests/a11y reads two windows apart through UI Automation and checks that a window a reader has read stays quiet at rest (no wake, no update). docs/accessibility.md lists the known limits (Linux and macOS, the toolkit's tree made again in each build, what grafted documents such as Wren's pages lack: iframes, caret and selection, text bounds, a second window).
• docs/getting-started.md and examples/hello: a new project with the toolkit as a submodule (prerequisites with the pinned Odin, MSVC, the optional Rust libraries; a window in a few lines built with -collection:gt=...; the render and text backends, accessibility, tests, versions) and the pitfalls met so far (the output folder, odin test deleting its exe, a render.Surface in a local, nested builds, keys, expect_assert on Windows). hello --frames=N runs without showing its window. Checked on a clean clone; tools/window_shot.ps1 accepts an absolute -Out.
• flate: DEFLATE, zlib and gzip as streams (Inflater / Deflater: input in chunks of any size, each push gives the output it allows; inflate / deflate for whole buffers), pure Odin for any platform. Checksums and sizes checked, a bound on the output (limit, Too_Large). The deflater writes each block in the cheapest of stored, fixed and dynamic Huffman codes (about 17 % smaller than fixed codes on text). Ported from Wren's src/flate (same API); docs/flate.md, tests/flate.
• Offscreen readback on the WebGPU backend: draw.offscreen_end gives a render.Readback_Id and render.readback_poll the picture (straight RGBA8, sRGB values, alpha kept) as under Direct3D 11: the frame copies the target into a buffer, the poll maps it without waiting (Pending until the GPU is done). tests/layers checks the pixels on both backends.
• ui.Build_Params.time_ms: the build's clock (caret blink, double and triple clicks, hover delays, timers, toasts), now_ms() when 0. A test or a replay passes its own to be deterministic; double clicks and the text selection's clicks now read the build's clock instead of the wall clock.

Fixed

• CI: two tests that failed now and then are deterministic. tests/ui_robust (nested_build_is_refused) checked an assertion through testing.expect_assert_message, whose exception handler on Windows races the system's end of the process: the whole test program ended without a message. The assertion is now caught on a thread of the test's own. tests/keyboard (caret_rect_is_where_the_caret_is_drawn) depended on the caret's blink phase, i.e. on how long the program had run (a slow WebGPU start blinked it off); it and the double-click tests (selection, panes) now pass time_ms. tools/test_windowless.ps1 and tools/test_backends.ps1 print the exit code of a failed package (an access violation, a trap nothing caught).