fix(monitoring): hostname, tooltip timestamps, default range (v0.5.1)

- Bug 1: Read hostname from /host/etc/hostname instead of os.Hostname()
  which returns the container ID inside Docker. Added volume mount.
- Bug 2: Tooltip callback used parsed.x (category index) instead of
  label (actual timestamp), showing 1970 dates.
- Bug 3+4: Default range changed from 24h to 1h so charts show data
  immediately on new deployments with limited history.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

controller/internal/metrics/sysinfo.go

@@ -16,8 +16,12 @@ import (
 func GetStaticInfo() StaticSystemInfo {
 	info := StaticSystemInfo{}
 
-	// Hostname
-	info.Hostname, _ = os.Hostname()
+	// Hostname — try host mount first, fall back to os.Hostname()
+	if data, err := os.ReadFile("/host/etc/hostname"); err == nil {
+		info.Hostname = strings.TrimSpace(string(data))
+	} else {
+		info.Hostname, _ = os.Hostname()
+	}
 
 	// OS — try host mount first, fall back to container's
 	info.OS = readOSRelease("/host/etc/os-release")