Initial commit: plasma DMD driver project

- Design docs: 12 V DC power supply, safety and bring-up, ESP32 interface, BOM
- PSU schematic (schemdraw) and KiCad 10 carrier-board project with HV net classes
- ESP32 PlatformIO firmware skeleton with HV watchdog toggle
- Reference schematic of the Stern 520-5138-00 display PSU

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

hardware/kicad/check_netlist.py

@@ -0,0 +1,53 @@
+"""Export the netlist with kicad-cli and compare it with PARTS in gen_kicad.py.
+
+    python hardware/kicad/check_netlist.py [path/to/kicad-cli]
+"""
+import re
+import subprocess
+import sys
+from pathlib import Path
+
+from gen_kicad import PARTS, PROJECT, pin_cache_for, read_sexpr_block
+
+HERE = Path(__file__).parent
+CLI = sys.argv[1] if len(sys.argv) > 1 else "C:/Users/patri/AppData/Local/Programs/KiCad/10.0/bin/kicad-cli.exe"
+net_file = HERE / f"{PROJECT}.net"
+subprocess.run([CLI, "sch", "export", "netlist", "-o", str(net_file), str(HERE / f"{PROJECT}.kicad_sch")],
+               check=True, capture_output=True)
+text = net_file.read_text(encoding="utf-8")
+net_file.unlink()
+
+# actual: (ref, pin number) -> net name
+actual = {}
+for m in re.finditer(r"\(net\s+\(code", text):
+    blk = read_sexpr_block(text, m.start())
+    name = re.search(r'\(name "([^"]*)"\)', blk).group(1).lstrip("/")
+    for ref, pin in re.findall(r'\(node\s+\(ref "([^"]+)"\)\s+\(pin "([^"]+)"\)', blk):
+        actual[(ref, pin)] = name
+
+errors = 0
+expected = {}
+for ref, lib_id, value, fp, conns, g in PARTS:
+    for num, name, *_ in pin_cache_for(lib_id):
+        key = num if num in conns else (name if name in conns else None)
+        if key is None or conns[key] is None:
+            continue
+        expected[(ref, num)] = conns[key]
+
+for k, net in expected.items():
+    got = actual.get(k)
+    if got != net:
+        errors += 1
+        print(f"MISMATCH {k}: expected {net}, got {got}")
+
+# every net should join at least two pins
+by_net = {}
+for k, net in actual.items():
+    by_net.setdefault(net, []).append(k)
+for net, nodes in sorted(by_net.items()):
+    if len(nodes) < 2 and not net.startswith("unconnected"):
+        errors += 1
+        print(f"SINGLE-PIN NET {net}: {nodes}")
+
+print(f"{len(expected)} pins checked, {len(by_net)} nets, {errors} problem(s)")
+sys.exit(1 if errors else 0)