Add gather-hardware-info.sh — auto-detects most report fields

Reads /proc, /sys, and common CLI tools (lscpu, lsblk, lspci, lsusb) to
print a YAML block matching data/schema.json: device model (DMI on x86,
/proc/device-tree/model on ARM SBCs), form factor (best-effort — battery
presence, DMI chassis type, device-tree presence), CPU, RAM, root storage
type/size, WiFi chip (PCI, then USB, then falls back to driver name rather
than guessing wrong), ethernet. Fields it can't detect (archy_version,
install_method, status) are left as clearly-marked TODOs rather than
guessed. Local-only — no network calls, changes nothing.

Tested for real on this box (a QEMU VM): correctly identified it as a VM,
correctly fell back to "other" with a TODO for form_factor rather than
guessing, output validated as parseable YAML. Passes shellcheck clean.

Linked from the homepage, report.html, and CONTRIBUTING.md.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

site/report.html

@@ -10,6 +10,7 @@
 <header>
   <h1><a href="index.html">ArchyHCL</a></h1>
   <p>Fill this in, hit submit — it opens a pre-filled issue on Gitea with everything formatted and ready for a maintainer to merge. You'll still need a (free) Gitea account to actually post it.</p>
+  <p>Not sure of your exact CPU/WiFi chip/storage? Run <a href="gather-hardware-info.sh">gather-hardware-info.sh</a> on the machine you tested first — it prints most of these fields for you.</p>
 </header>
 
 <main>