feat(admin-ui): add /virtual-tags, /scripted-alarms, and /script-log pages (tasks #25, #26, #27)

Gap 2 (#25): VirtualTagsTab.razor + /virtual-tags global page — list/create/toggle
virtual tags per draft generation with DataType, Script, trigger, Historize, Enabled
fields. Tab wired into DraftEditor.

Gap 3 (#26): ScriptedAlarmsTab.razor + /scripted-alarms global page — list/create
scripted alarms with AlarmType, Severity, MessageTemplate, PredicateScript,
HistorizeToAveva, Retain. SeverityBand helper shows Low/Medium/High/Critical label.
Tab wired into DraftEditor.

Gap 4 (#27): ScriptLogHub (SignalR IAsyncEnumerable stream) tails scripts-*.log with
optional ScriptName filter; ScriptLog.razor provides Start/Stop/Clear controls plus
level filter dropdown. Hub registered at /hubs/script-log in Program.cs.

Nav rail gains a "Scripting" eyebrow with entries for all three pages.
19 new unit tests for ScriptLogHub parse/filter/tail helpers (Category=Unit).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/Server/ZB.MOM.WW.OtOpcUa.Admin/Components/Layout/MainLayout.razor

@@ -30,6 +30,10 @@
         <NavLink class="rail-link" href="/reservations" Match="NavLinkMatch.Prefix">Reservations</NavLink>
         <NavLink class="rail-link" href="/certificates" Match="NavLinkMatch.Prefix">Certificates</NavLink>
         <NavLink class="rail-link" href="/role-grants" Match="NavLinkMatch.Prefix">Role grants</NavLink>
+        <div class="rail-eyebrow">Scripting</div>
+        <NavLink class="rail-link" href="/virtual-tags" Match="NavLinkMatch.Prefix">Virtual tags</NavLink>
+        <NavLink class="rail-link" href="/scripted-alarms" Match="NavLinkMatch.Prefix">Scripted alarms</NavLink>
+        <NavLink class="rail-link" href="/script-log" Match="NavLinkMatch.Prefix">Script log</NavLink>
 
         <div class="rail-foot">
             <AuthorizeView>