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/tasks.go

@@ -140,7 +140,8 @@ type taskParams struct {
 	Device             string      `json:"device,omitempty"` // for install
 	LBAF               int         `json:"lbaf,omitempty"`
 	PlatformComponents []string    `json:"platform_components,omitempty"`
-	SAADmiChanges      []saaChange `json:"saa_dmi_changes,omitempty"`
+	SAADmiChanges      []saaChange  `json:"saa_dmi_changes,omitempty"`
+	FRUChanges         []fruChange  `json:"fru_changes,omitempty"`
 }
 
 type persistedTask struct {