Advance PCB carrier to A1 layout

Reposition the ESP32 and RS-232 reference within the notched outline,
preserve the A0 snapshot, and add second-pass two-layer routing
evidence.
Refresh validation reports and draft previews while keeping fabrication
status provisional.

hardware/PCB/validation/pcb-routing-preservation.py

@@ -0,0 +1,99 @@
+#!/usr/bin/python3
+"""Compare A1 against the untouched A0 snapshot, including unrelated graphics."""
+import hashlib
+import json
+from pathlib import Path
+import re
+import uuid
+
+ROOT=Path(__file__).resolve().parent.parent
+OUT=ROOT/'validation'
+
+
+def parse(path):
+    tokens=iter(re.findall(r'"(?:\\.|[^"\\])*"|[()]|[^\s()]+',path.read_text()))
+    def group():
+        result=[]
+        for token in tokens:
+            if token==')':
+                return result
+            result.append(group() if token=='(' else token)
+        raise ValueError('unterminated S-expression')
+    assert next(tokens)=='('
+    return group()
+
+
+def child(item,key):
+    return next(v for v in item if isinstance(v,list) and v[0]==key)
+
+
+def ident(item):
+    return child(item,'uuid')[1].strip('"')
+
+
+def sha(path):
+    return hashlib.sha256(path.read_bytes()).hexdigest()
+
+
+report=json.loads(OUT.joinpath('pcb-routing-reposition.json').read_text())
+a0=OUT/'pcb-a0-before-reposition.kicad_pcb'
+a1=ROOT/'serial-carrier.kicad_pcb'
+assert sha(a0)==report['a0_snapshot_sha256'], 'A0 snapshot changed'
+assert sha(OUT/'pcb-routing-input.kicad_pcb')==report['a1_unrouted_sha256'], 'A1 routing input changed'
+# These two handoff documents are intentionally updated during A1 integration.
+protected={name:digest for name,digest in report['protected_file_sha256'].items()
+           if name not in ('README.md','pcb-draft-notes.md')}
+for name,digest in protected.items():
+    assert sha(ROOT/name)==digest, 'protected file changed: '+name
+old,new=parse(a0),parse(a1)
+old_fp={ident(x):x for x in old if isinstance(x,list) and x[0]=='footprint'}
+new_fp={ident(x):x for x in new if isinstance(x,list) and x[0]=='footprint'}
+assert set(old_fp)==set(new_fp)
+for key,fp in old_fp.items():
+    # Footprint geometry, fields, UUIDs and connectivity must be identical;
+    # only the top-level placement may differ, and only for the four moves.
+    ref=next(v[2].strip('"') for v in fp if isinstance(v,list) and v[:2]==['property','"Reference"'])
+    cleaned=lambda f:[v for v in f if not isinstance(v,list) or v[0]!='at']
+    assert cleaned(fp)==cleaned(new_fp[key]), 'footprint content changed: '+ref
+    if ref not in report['moves_local_mm']:
+        assert child(fp,'at')==child(new_fp[key],'at'),ref
+    else:
+        expected=report['moves_local_mm'][ref][1]
+        assert [round(float(v)-100,6) for v in child(new_fp[key],'at')[1:3]]==expected,ref
+ns=uuid.UUID('67964aa4-c3a5-45d8-9b54-250fb68e7c41')
+owned={str(uuid.uuid5(ns,str(i))) for i in range(4096)}
+cad_ns=uuid.UUID('ba7274a8-c35d-46bc-908d-cd86708fc6c4')
+cad_owned={str(uuid.uuid5(cad_ns,str(i))) for i in range(7)}
+changed_texts=set(report['changed_board_text_uuids'])
+for item in old:
+    if isinstance(item,list) and item[0]=='gr_text':
+        value=json.loads(item[1])
+        if value=='82 x 80 mm / 2 copper layers' or value.startswith('DE-9 OUT /'):
+            changed_texts.add(ident(item))
+
+def drawings(tree):
+    return {ident(x):x for x in tree if isinstance(x,list) and
+            (x[0].startswith('gr_') or x[0] in ('dimension','target','image'))}
+
+old_gr,new_gr=drawings(old),drawings(new)
+edge_ids={key for key,value in old_gr.items() if child(value,'layer')[1]=='"Edge.Cuts"'}
+assert cad_owned <= set(new_gr), 'missing CAD projection graphics'
+assert all(child(new_gr[key],'layer')[1]=='"Dwgs.User"' for key in cad_owned)
+excluded=owned|cad_owned|changed_texts|edge_ids
+unchanged_old={key:value for key,value in old_gr.items() if key not in excluded}
+unchanged_new={key:value for key,value in new_gr.items() if key not in excluded}
+assert unchanged_old==unchanged_new, 'unrelated board graphics changed'
+assert set(old_gr)-owned==set(new_gr)-owned-cad_owned, 'non-owned board graphic UUID set changed'
+assert [x for x in old if isinstance(x,list) and x[0]=='net']==[x for x in new if isinstance(x,list) and x[0]=='net']
+assert not (ROOT/'~serial-carrier.kicad_pcb.lck').exists(), 'PCB reopened before handoff'
+result=dict(a0_snapshot_unchanged=True,a1_unrouted_snapshot_unchanged=True,
+            protected_files_unchanged=list(protected),
+            intentional_documentation_updates=['README.md','pcb-draft-notes.md'],
+            cad_projection_graphics=len(cad_owned),
+            footprints_identical_except_authorized_placement=True,
+            footprint_count=len(old_fp),unrelated_board_graphics_preserved=len(unchanged_old),
+            non_owned_board_graphic_uuids_preserved=True,
+            refreshed_device_silkscreen_items=len(set(new_gr)&owned),
+            pcb_editor_lock_absent=True,final_board_sha256=sha(a1))
+OUT.joinpath('pcb-routing-preservation.json').write_text(json.dumps(result,indent=2)+'\n')
+print(json.dumps(result,indent=2))