make the test suite and openapi generator platform-independent

Windows checkouts turned LF into CRLF (core.autocrlf=true), and several
tests plus the openapi generator hardcoded LF or POSIX path separators.
The result was a suite that was green on Linux CI but red on Windows, and
an openapi.json whose /api/hermes/* routes silently disappeared when
generated on Windows.

Pin the repository to LF via .gitattributes, strip shebangs before
Vite's SSR transform, and key route files by their posix path. Add a
manually triggered macOS verification workflow so the same checks run
on a self-hosted macOS runner.

tests/server/gateway-respawn.test.ts

@@ -205,7 +205,11 @@ describe('gateway-runner supervision', () => {
     startGatewayRunManaged('/usr/bin/hermes', { profileDir: '/tmp/delete-me' })
     expect(fakeChildren).toHaveLength(1)
 
-    const retired = retireManagedGatewayForProfile('/tmp/delete-me', { timeoutMs: 5000 })
+    // 固定 platform：停止网关的手段随平台不同（POSIX 走 child.kill('SIGTERM')，
+    // Windows 走 taskkill 杀进程树），不固定的话这个用例会随运行平台变形。
+    // Windows 分支由同文件末尾的 "kills the managed gateway process tree on
+    // Windows shutdown" 单独覆盖。
+    const retired = retireManagedGatewayForProfile('/tmp/delete-me', { timeoutMs: 5000, platform: 'linux' })
     expect(fakeChildren[0].killSignals).toEqual(['SIGTERM'])
 
     fakeChildren[0].emit('exit', 0, 'SIGTERM')
@@ -226,7 +230,7 @@ describe('gateway-runner supervision', () => {
     startGatewayRunManaged('/usr/bin/hermes', { profileDir: '/tmp/shutdown-b' })
     expect(fakeChildren).toHaveLength(2)
 
-    const shutdown = shutdownManagedGateways({ timeoutMs: 5000 })
+    const shutdown = shutdownManagedGateways({ timeoutMs: 5000, platform: 'linux' })
 
     expect(fakeChildren[0].killSignals).toEqual(['SIGTERM'])
     expect(fakeChildren[1].killSignals).toEqual(['SIGTERM'])
@@ -266,7 +270,7 @@ describe('gateway-runner supervision', () => {
 
     startGatewayRunManaged('/usr/bin/hermes', { profileDir: '/tmp/shutdown-d' })
 
-    const shutdown = shutdownManagedGateways({ timeoutMs: 1000 })
+    const shutdown = shutdownManagedGateways({ timeoutMs: 1000, platform: 'linux' })
     expect(fakeChildren[0].killSignals).toEqual(['SIGTERM'])
 
     await vi.advanceTimersByTimeAsync(1000)