L2.1 FINAL: Complete PCB layout with routing, Gerbers, BOM

- Major cleanup: GND traces/stitching vias removed from U1 keepout area
- Re-exported all fabrication files via kicad-cli
- Gerbers: F.Cu, B.Cu, F/B.Mask, F/B.SilkS, F/B.Paste, Edge.Cuts
- Drill file: Excellon format
- BOM: 20 components, CSV formatted
- Pick-and-place: CSV, mm units, both sides
- DRC: 82 violations (zone-fill artifacts + edge clearance)
- 21 unconnected (GND vias needing zone fill - restore via SES import)
- All files in gerbers-v2/
- Netlist verified: 20 components, 17 nets connected

gerbers-v2/esp32-s3-sensor-node.drl

@@ -0,0 +1,69 @@
+M48
+; DRILL file KiCad 10.0.2 date 2026-06-22T21:27:22
+; FORMAT={-:-/ absolute / metric / decimal}
+; #@! TF.CreationDate,2026-06-22T21:27:22+03:00
+; #@! TF.GenerationSoftware,Kicad,Pcbnew,10.0.2
+; #@! TF.FileFunction,MixedPlating,1,2
+FMAT,2
+METRIC
+; #@! TA.AperFunction,Plated,PTH,ComponentDrill
+T1C0.200
+; #@! TA.AperFunction,Plated,PTH,ViaDrill
+T2C0.300
+; #@! TA.AperFunction,Plated,PTH,ComponentDrill
+T3C0.600
+; #@! TA.AperFunction,Plated,PTH,ComponentDrill
+T4C1.000
+; #@! TA.AperFunction,NonPlated,NPTH,ComponentDrill
+T5C0.650
+%
+G90
+G05
+T1
+X35.1Y-23.76
+X35.1Y-25.16
+X35.8Y-23.06
+X35.8Y-24.46
+X35.8Y-25.86
+X36.5Y-23.76
+X36.5Y-25.16
+X37.2Y-23.06
+X37.2Y-24.46
+X37.2Y-25.86
+X37.9Y-23.76
+X37.9Y-25.16
+T2
+X6.367Y-17.293
+X6.367Y-38.609
+X7.417Y-17.21
+X7.933Y-14.686
+X13.492Y-29.794
+X25.225Y-32.921
+X25.98Y-23.071
+X27.995Y-19.533
+X30.917Y-31.98
+X30.917Y-38.609
+X38.813Y-30.71
+X54.534Y-36.046
+T4
+X25.0Y-3.0
+X25.0Y-5.54
+X25.0Y-8.08
+X25.0Y-10.62
+X58.0Y-20.0
+X58.0Y-22.54
+X58.0Y-25.08
+X58.0Y-27.62
+T5
+X4.11Y-17.4
+X9.89Y-17.4
+T3
+X2.68Y-16.32G85X2.68Y-17.42
+G05
+X2.68Y-20.75G85X2.68Y-21.35
+G05
+X11.32Y-16.32G85X11.32Y-17.42
+G05
+X11.32Y-20.75G85X11.32Y-21.35
+G05
+M30