Restructure project documentation

Separate operator guides from development contracts, relocate
implementation notes under `docs/devel/`, and update cross-references
and
hardware tooling paths. Add getting-started, user administration, and
firmware update guides while preserving firmware behavior.

hardware/PCB/validate_pcb_draft.py

@@ -126,4 +126,4 @@ summary={
 (OUT/"pcb-validation-summary.json").write_text(json.dumps(summary,indent=2)+"\n")
 print("PCB draft verified: 82 x 80 mm; 2 copper layers; 0 physical DRC violations; 0 unrouted.")
 print("All schematic pad nets match. One expected U2 footprint parity warning remains visible.")
-print("Not fabrication-ready; see pcb-draft-notes.md and ignored checks in the DRC report.")
+print("Not fabrication-ready; see ../../docs/devel/hardware/PCB/pcb-draft-notes.md and ignored checks in the DRC report.")