feat(inventory): deep hardware capture + per-probe substeps + verbose logs

Extend Inventory stage from a one-liner summary to a per-probe substep
emitter with ~20-30 narrative log lines per run.

- spec: per-DIMM memory (slot/size/speed/manufacturer/part_number),
  richer CPU (vendor/stepping/physical_cores/flags), disk
  model/transport/rotational, NIC driver/pci_addr, GPU vram/pci/driver,
  new System/Baseboard/PSU/OS top-level sections. All fields omitempty
  so existing expected-spec YAML and artifacts stay compatible.
- spec.Diff: new diffDIMMs/diffSystem/diffBaseboard/diffPSU/diffOS
  helpers; extended diffDisks/diffNICs/diffGPUs for new fields. GPU
  diff gains PCIAddr-pinned matching alongside count-by-model.
- agent/probes/inventory: CPU (/proc/cpuinfo extended), Memory
  (dmidecode -t 17 multi-block), Disks (+model/transport/rotational),
  NICs (+driver/pci from sysfs), GPUs (VRAM from lspci -vv),
  new System/Baseboard (dmidecode -t system/baseboard), PSU
  (dmidecode -t 39), OS (/proc/sys/kernel/osrelease + /etc/os-release).
  All probes accept a Logger and emit per-finding info/warn lines.
- agent/probes/firmware: parseDmidecodeAllSections for multi-block
  fixtures (memory / PSU).
- agent/runner: Inventory case becomes 9 substep rows (CPU / Memory /
  Disks / NICs / GPUs / System / Baseboard / PSU / OS) with per-probe
  start/complete timestamps.
- report: new Inventory HTML section between Stages and Firmware;
  resolveReporting loads the inventory.json artifact.
- agent/tests/fakes/dmidecode: dispatches on -t flag to serve bios /
  memory / system / baseboard / 39 fixtures for unit tests.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

internal/api/agent_handlers.go

@@ -1201,6 +1201,14 @@ func (a *Agent) resolveReporting(r *http.Request, runID int64) {
 			log.Printf("reporting: list firmware: %v", err)
 		}
 	}
+	// Inventory is optional for reporting: runs cancelled before the
+	// Inventory stage finishes won't have the artifact. Failure to load
+	// is logged but never aborts the report.
+	inventory, err := a.readInventoryArtifact(r, runID)
+	if err != nil {
+		log.Printf("reporting: read inventory: %v", err)
+		inventory = nil
+	}
 	bundle := map[string]any{
 		"run":          run,
 		"host":         host,
@@ -1256,6 +1264,7 @@ func (a *Agent) resolveReporting(r *http.Request, runID int64) {
 			SpecDiffs:   diffs,
 			Aggregates:  report.AggregateMeasurements(measurements),
 			Firmware:    fwRows,
+			Inventory:   inventory,
 		}
 		if htmlBuf, err := report.RenderHTML(htmlData); err != nil {
 			log.Printf("reporting: render html: %v", err)