feat: add Windows headed browser foundation

.gitignore

@@ -1,6 +1,25 @@
 /.zig-cache/
 /.lp-cache/
+/.lp-cache-win/
 zig-out
 lightpanda.id
 /src/html5ever/target/
+/html5ever-test/
 src/snapshot.bin
+/_link_trace.log
+/_msvc_link.log
+/_msvc_use_lld_false.log
+/_msvc_use_lld_false_rel.log
+/tmp-browser-smoke/**/*.stdout.txt
+/tmp-browser-smoke/**/*.stderr.txt
+/tmp-browser-smoke/**/*.out.txt
+/tmp-browser-smoke/**/*.err.txt
+/tmp-browser-smoke/**/*.before.png
+/tmp-browser-smoke/headed-smoke.png
+/tmp-browser-smoke/links.bmp
+/tmp-browser-smoke/flow-layout/flow-layout.png
+/tmp-browser-smoke/image-smoke/headed-image-smoke.png
+/tmp-browser-smoke/inline-flow/inline-flow.png
+/tmp-browser-smoke/multi-image/multi-image.png
+/tmp-browser-smoke/wrapped-link/wrapped-before.png
+/tmp-browser-smoke/wrapped-link/wrapped-base-before.png

README.md

@@ -123,6 +123,35 @@ INFO  app : server running . . . . . . . . . . . . . . . . .  [+0ms]
       address = 127.0.0.1:9222
 ```
 
+### Browser mode switch (fork)
+
+This fork adds a browser mode switch on `fetch` and `serve`:
+
+```console
+./lightpanda serve --browser_mode headed
+```
+
+Shortcuts are available:
+- `--headed`
+- `--headless`
+
+`headed` is currently experimental.
+- On Windows targets, it starts a native headed window lifecycle backend.
+- Windows headed mode now forwards native mouse (down/up/move/wheel/hwheel), click, keydown/keyup (including repeat state), text input (`WM_CHAR`/`WM_UNICHAR`), IME result/preedit composition messages (`WM_IME_COMPOSITION`), back/forward mouse buttons, and window blur into page input, with caret-aware text insertion, `Ctrl/Meta + A` select-all, word-wise caret/edit shortcuts (`Ctrl/Meta + ArrowLeft/ArrowRight`, `Ctrl/Meta + Backspace/Delete`), textarea vertical/line navigation (`ArrowUp/ArrowDown`, line-aware `Home/End`, document `Ctrl/Meta + Home/End`), `Tab`/`Shift+Tab` focus traversal (including positive `tabindex` ordering), and native clipboard shortcuts (`Ctrl/Meta + C/X/V`, `Ctrl+Insert`, `Shift+Insert`, `Shift+Delete`) for text controls. Clipboard shortcuts now dispatch cancelable `copy`/`cut`/`paste` events first and respect `preventDefault()`.
+- On non-Windows targets, it safely falls back to headless execution.
+
+Viewport sizing is configurable for both modes:
+- `--window_width <px>`
+- `--window_height <px>`
+
+CDP viewport control is also wired in this fork:
+- `Emulation.setDeviceMetricsOverride`
+- `Emulation.clearDeviceMetricsOverride`
+- `Browser.setWindowBounds` (width/height)
+
+Windows run/build guide for this fork:
+- [`docs/WINDOWS_FULL_USE.md`](docs/WINDOWS_FULL_USE.md)
+
 Once the CDP server started, you can run a Puppeteer script by configuring the
 `browserWSEndpoint`.