Add native Windows ARM64 beta devkits and application builds

Windows builds currently force x64, including when Hutch runs on ARM64. Select the Windows target throughout Zig/MSVC, WebView2, CEF, the native wrapper, launcher/core/extractor, and owned dependency downloads. Publish and validate ARM64 devkit/release/npm artifacts, and cover both renderers in the Kitchen and VM matrices. Odin remains unsupported on Windows ARM64.

Pin the published ARM64 leaf dependencies and prepare Hutch 0.27.2-canary.1 / Cottontail 0.7.2-canary.2 as build tools and application runtime. Those two canaries must be published and verified before this PR is merged or an Electrobun beta is tagged. Update the support documentation for the interpreter-only JSC preview and explicit architecture installation.

Native Windows ARM64 validation: complete core devkit build and PE checks; launcher/profile-path checks; all six Zig/Rust/Go Kitchen renderer combinations passed (Zig WebView2 69 tests; the other five 70 each). Release/npm contracts: 116 passed, 5 platform skips. Native Cottontail manifest, build-target, dependency-selection and Kitchen planning checks passed. Cottontail Kitchen also passed on both renderers: 129 tests with WebView2 (2 skips), 131 with CEF, both clean shutdowns. These app checks used the frozen local ARM64 runtime; the final public-SDK Cottontail release binary separately passed its FFI, hashing and JSC ABI gates. Bun Kitchen also passed on both renderers: 129 tests with WebView2 (2 skips), 131 with CEF, both clean shutdowns. All ten supported main-process/renderer combinations have passed on this ARM64 VM. Both Cottontail Kitchen variants were rebuilt with the final 0.7.2-canary.2 runtime from the public JSC SDK, using native ARM64 build tools; the repeated WebView2 129/2-skip and CEF 131-test runs passed with clean shutdowns. Final published-toolchain verification remains pending the canary releases.

Release scope: Electrobun beta only. Automatic x64-to-ARM64 migration is a separate remaining step; existing installations keep their architecture.