fix(web): dashboard review fixes — real health status contract, dedupe version fetch, refresh guard (#109)

- Match the backend's exact health status contract ('pass'|'fail'|'warn'|'info')
  instead of fictional strings; 'info' now renders as a neutral/idle presentation
  and is excluded from failing/warning counts in summarizeHealth.
- Drop the redundant /api/version fetch from getDashboardData/DashboardData;
  SidebarVersion's useDashboardVersionQuery remains the single source.
- Disable "Refresh health" (via Button's loading prop) while a health request
  is in flight to prevent concurrent double-click requests.
- Add the active-flag unmount guard to useDashboardHealthQuery for consistency
  with useDashboardQuery/useChannelsQuery.
- Remove dead .ctv-activity-*/.ctv-release-* CSS left over from the removed
  activity feed/release notes UI.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

web/src/shell.css

@@ -442,7 +442,6 @@
 }
 
 .ctv-onair-head code,
-.ctv-activity-list code,
 .ctv-live-channel-row code {
   color: var(--text-secondary);
   font-family: var(--font-mono, ui-monospace, monospace);
@@ -516,8 +515,7 @@
   gap: var(--space-7, 16px);
 }
 
-.ctv-health-panel,
-.ctv-activity-feed {
+.ctv-health-panel {
   display: grid;
 }
 
@@ -535,8 +533,7 @@
   border-top: 0;
 }
 
-.ctv-health-icon,
-.ctv-activity-icon {
+.ctv-health-icon {
   width: 24px;
   height: 24px;
   display: inline-flex;
@@ -586,69 +583,6 @@
   padding: var(--space-4, 8px) var(--space-6, 12px);
 }
 
-.ctv-activity-row {
-  min-height: 44px;
-  display: grid;
-  grid-template-columns: auto auto minmax(0, 1fr) auto;
-  align-items: center;
-  gap: var(--space-4, 8px);
-  border-top: 1px solid var(--border-hairline);
-  padding: 0 var(--space-6, 12px);
-}
-
-.ctv-activity-row:first-child {
-  border-top: 0;
-}
-
-.ctv-activity-row > span:nth-child(3) {
-  overflow: hidden;
-  color: var(--text-primary);
-  text-overflow: ellipsis;
-  white-space: nowrap;
-}
-
-.ctv-activity-row code,
-.ctv-release-toggle code {
-  color: var(--text-disabled);
-  font-family: var(--font-mono, ui-monospace, monospace);
-  font-size: var(--text-2xs, 11px);
-}
-
-.ctv-release-toggle {
-  width: 100%;
-  display: grid;
-  grid-template-columns: auto auto minmax(0, 1fr) auto;
-  align-items: center;
-  gap: var(--space-4, 8px);
-  border: 0;
-  background: transparent;
-  color: var(--text-primary);
-  cursor: pointer;
-  padding: 0;
-  text-align: left;
-}
-
-.ctv-release-toggle svg:first-child {
-  color: var(--action-primary);
-}
-
-.ctv-release-toggle code {
-  justify-self: end;
-}
-
-.ctv-release-body {
-  display: grid;
-  gap: var(--space-3, 6px);
-  margin-top: var(--space-6, 12px);
-  color: var(--text-secondary);
-  font-size: var(--text-xs, 12px);
-  line-height: 1.45;
-}
-
-.ctv-release-body p {
-  margin: 0;
-}
-
 .ctv-live-channel-body {
   min-height: 96px;
 }