Collect IPMI sensors, SEL and dmesg errors into audit JSON and support bundle

- audit JSON: IPMI sensor readings (ipmitool sensor) merged into hardware.sensors alongside lm-sensors data
- audit JSON: IPMI SEL entries (ipmitool sel list) in hardware.event_logs with source "ipmi-sel"
- audit JSON: dmesg error/warning lines in hardware.event_logs with source "dmesg" (filtered by error/warn/AER/Xid/NVRM/ECC/panic patterns)
- support bundle: added ipmitool-sensor.txt, ipmitool-sel.txt, ipmitool-sel-time.txt to techdump
- saa_dmi.go: fix dmiItemRE to accept SHN with parentheses (e.g. PS(4)LC for PSU fields)

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

audit/internal/webui/saa_dmi.go

@@ -28,7 +28,8 @@ var (
 	shnRE        = regexp.MustCompile(`^[A-Za-z0-9_]{1,16}$`)
 	dmiSectionRE = regexp.MustCompile(`^\[(.+?)\]$`)
 	// Item Name   {SHN}   = value   // comment
-	dmiItemRE    = regexp.MustCompile(`^(.+?)\s+\{([A-Za-z0-9]{1,16})\}\s*=\s*(.*)$`)
+	// SHN may contain parentheses, e.g. {PS(4)LC} for power supply fields
+	dmiItemRE    = regexp.MustCompile(`^(.+?)\s+\{([A-Za-z0-9_()\-]{1,24})\}\s*=\s*(.*)$`)
 	dmiVersionRE = regexp.MustCompile(`(?i)^version\s*=`)
 )