app: startup steps in the crash journal, and a Windows exception filter (#299)

egui-wgpu's startup hook and the app's own steps (window, app setup, viewport
pipelines, first frame, running) go into the journal. On Windows,
native_crash.rs (adapted from SolidCraft, the only module allowed unsafe code;
the app crate now denies instead of forbids it) writes the exception code,
faulting module and offset and a minidump. A nightly/on-demand CI job runs the
app's tests on Windows, including a child that faults on purpose.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UhhZMBTviDQxZvwnyP89fo

Cargo.lock

@@ -1286,6 +1286,7 @@ dependencies = [
  "serde_json",
  "signal-hook",
  "ureq",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]