Add IPMI FRU editor to Tools page

- New card "IPMI — FRU" on Tools page (device 0, in-band)
- Read: GET /api/tools/ipmi-fru → ipmitool fru print 0 → editable table
- Editable fields: chassis (part#, serial, extra), board (mfr, product, serial, part#),
  product (mfr, name, part#, version, serial); read-only fields displayed as text
- Write: POST /api/tools/ipmi-fru/write → task → backup to fru-backups/ → ipmitool fru edit per field
- Dirty tracking + Save (N changed) button, same UX as Supermicro DMI card

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

audit/internal/webui/page_export_tools.go

@@ -404,7 +404,9 @@ loadNvidiaSelfHeal();
 func renderTools() string {
 	return renderNVMeFormatCard() + `
 
-` + renderSAADMICard()
+` + renderSAADMICard() + `
+
+` + renderIPMIFRUCard()
 }
 
 func renderExportIndex(exportDir string) (string, error) {