chore: import upstream snapshot with attribution

example/wasm-key-encode/README.md

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+# WebAssembly Key Encoder Example
+
+This example demonstrates how to use the Ghostty VT library from WebAssembly
+to encode key events into terminal escape sequences.
+
+## Building
+
+First, build the WebAssembly module:
+
+```bash
+zig build -Demit-lib-vt -Dtarget=wasm32-freestanding -Doptimize=ReleaseSmall
+```
+
+This will create `zig-out/bin/ghostty-vt.wasm`.
+
+## Running
+
+**Important:** You must serve this via HTTP, not open it as a file directly.
+Browsers block loading WASM files from `file://` URLs.
+
+From the **root of the ghostty repository**, serve with a local HTTP server:
+
+```bash
+# Using Python (recommended)
+python3 -m http.server 8000
+
+# Or using Node.js
+npx serve .
+
+# Or using PHP
+php -S localhost:8000
+```
+
+Then open your browser to:
+
+```
+http://localhost:8000/example/wasm-key-encode/
+```
+
+Focus the text input field and press any key combination to see the encoded output.