hub resource limits (#900)

- Feature: Hub dashboard now shows a Resources tile with disk and memory usage against configured limits
- Feature: Hub module listing now shows state-change timestamps and duration for each instance
- Improvement: Hub provisioning rejects new instances when disk or memory usage exceeds configurable thresholds; limits are disabled by default (0 = no limit)
  - `--hub-provision-disk-limit-bytes` - Reject provisioning when used disk exceeds this many bytes
  - `--hub-provision-disk-limit-percent` - Reject provisioning when used disk exceeds this percentage of total disk
  - `--hub-provision-memory-limit-bytes` - Reject provisioning when used memory exceeds this many bytes
  - `--hub-provision-memory-limit-percent` - Reject provisioning when used memory exceeds this percentage of total RAM
- Improvement: Hub process metrics are now tracked atomically per active instance slot, eliminating per-query process handle lookups
- Improvement: Hub, Build Store, and Workspaces service stats sections in the dashboard are now collapsible
- Bugfix: Hub watchdog loop did not check `m_ShutdownFlag`, causing it to spin indefinitely on shutdown

1 files changed, 4 insertions, 0 deletions

diff --git a/src/zenserver/frontend/html/zen.css b/src/zenserver/frontend/html/zen.css
index d9f7491ea..cb3d78cf2 100644
--- a/src/zenserver/frontend/html/zen.css
+++ b/src/zenserver/frontend/html/zen.css
@@ -816,6 +816,10 @@ zen-banner + zen-nav::part(nav-bar) {
 	border-color:		var(--theme_p0);
 }
 
+.stats-tile[data-over="true"] {
+	border-color:		var(--theme_fail);
+}
+
 .stats-tile-detailed {
 	position:			relative;
 }