feat(startup): name an Edge blocker instead of hanging

Confirmed on the machine that started this: an 'Edge blocker' utility was
in the way, and unblocking Edge fixed the launch.

Those tools work by registering a Debugger entry under Image File
Execution Options for msedge.exe and msedgewebview2.exe, so Windows
refuses to run the process. The runtime is installed and registers its
version quite happily — which is why the logs showed WebView2 present —
and then never starts. OpsLog draws its whole interface with that engine,
so the window never opened: no error, no crash, a process sitting there
doing nothing.

That entry is read at startup now and said plainly, in the log and on
screen, with the one thing that helps: unblock Edge in the tool that
blocked it. Reinstalling OpsLog cannot fix a machine in this state, and
that is where an unexplained silence sends people.

Also logs the Windows build and which Edge policies are set — value names
only, never their contents: a policy key holds URLs and account names
that are nobody's business here.

webview2_other.go

@@ -8,3 +8,9 @@ func webView2Version() string { return "n/a" }
 
 // windowsVersion is a Windows question too.
 func windowsVersion() string { return "n/a" }
+
+// edgePolicyNotes is a Windows question too.
+func edgePolicyNotes() string { return "n/a" }
+
+// edgeExecutionBlocked is a Windows question too.
+func edgeExecutionBlocked() string { return "" }